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Eggs of Carpophilus hemipterus (L.) (Coleoptera: Nitidulidae), Lasioderma serricorne (F.) (Coleoptera: Anobiidae), Ephestia elutella (Hiibner) (Lepidoptera: Pyralidae), and Amyelois transitella (Walker) (Lepidoptera: Pyralidae) were imaged using scanning electron microscopy to explore how respiratory openings on the chorion surface may affect the relative efficacy of fumigation. Each C. hemipterus egg had two aeropyles and no micropyles; A. transitella and L. serricorne eggs had many aeropyles and several micropyles; and each E. elutella egg had many aeropyles and a single micropyle. Our data suggest that gases, including fumigants, differentially diffuse into the eggs of these species, with penetration through aeropyles and micropyles likely occurring to a greater extent in L. serricorne, E. elutella, and A. transitella than in C. hemipterus. Although confirmatory measurements of fumigant diffusion into eggs are needed, these findings suggest that species-specific ovicidal efficacies are related, at least in part, to the surface morphology of eggs and that chorionic respiratory structures differentially affect fumigant penetration and/or uptake.
Dendroctonus frontalis Zimmermann is considered one of the most important economic and ecological forest pests in the United States, Mexico, and Central America. Recently, two apparent morphological variants of this species were discovered occurring syntopically in Central America and southern Mexico. Morphotype A beetles lack a series of fine parallel ridges on the episternal area of the prothorax that are present on morphotype B. The goal of the present work was to clarify the taxonomic status of the morphotypes of the D. frontalis species complex. Geometric morphometric analyses of seminal rod and spermatheca shape together with the characterization of 16 attributes of external morphology revealed differences in quantitative and qualitative characters that distinguished adults of the two morphotypes from each other as well as from the closely related species Dendroctonus vitei Wood and Dendroctonus mexicanus Hopkins. Karyotype analysis of morphotype B revealed a chromosomal formula (5AA Xyp) distinct from that found in morphotype A previously reported for D. frontalis (7AA Xyp). In the laboratory, forced intermorphotype crosses produced F1 progeny but at lower frequency than intramorphotype pairings, and dissections of spermatheca revealed a lower frequency of insemination at least one type of heterotypic cross. Phylogenetic analysis of the D. frontalis species complex based on 786 bp of the cytochrome oxidase I gene indicated that morphotypes B and A are two independent groups with 98% nodal support within D. frontalis. These data provide compelling evidence that the two syntopic morphotypes represent two distinct sibling species.
Ectobius kohlsi sp. n. and three undetermined species of the common Eurasian cockroach genus EctobiusStephens, 1835 are reported from the lower middle Eocene of North America. This species indicates a cosmopolitan distribution of the genus during the mid Paleogene, and supports its current relict distribution in modern north-temperate and African ecosystems. When compared with the living species, E. kohlsi was either neutral or plesiomorphic in all characters, but exhibited a close relationship to the extant Ectobius kraussianusRamme, 1923 Species Group in the identical structure of the pronotum. E. kohlsi also was similar to extant Ectobius ticinusBohn, 2004, in the character of its wing venation (see Bohn 2004), in particular the forewing vein M, and to extant Ectobius vittiventris (Costa 1847) in details of forewing coloration. These latter two species are members of the Ectobius sylvestris Species Group (Bohn 1989). Ectobius balticusGermar et Berendt, 1856 —a conspicuously dominant cockroach from mid-Eocene Baltic amber—also appears plesiomorphic in all characters despite being a few million years younger than E. kohlsi. One reason for the complete disappearance of this dominant genus from North America is the peculiar consequence that, after 49 million years, a cool-adapted Ectobius lapponicus (L.) was capable of being reintroduced to a significantly cooler North America than that its antecedents which inhabited North America during a warmer European Eocene. Modern E. lapponicus is synanthropic in North America, even though no synanthropism is recorded for this species in its native habitat throughout Europe.
Armored scale insects include invasive economic pests that have been widely studied in human-altered habitats but have received less attention in natural habitats. Although armored scale insects are nearly ubiquitous associates of woody plants, they generally go uncollected in general surveys because they are not susceptible to mass collecting techniques, such as fogging, beating, or trapping. San Lorenzo National Park in Panama was the subject of a recent high-profile effort to quantify the arthropod diversity in a tropical forest (Basset et al. 2012). Here, we contribute to understanding the biodiversity of this classic site by reporting the armored scale insect species we found there in August 2010. We found that, unlike other rainforest canopy taxa, the armored scale insect fauna is dominated by highly polyphagous cosmopolitan pests. However, we also found new species, and we describe two of them here: Furcaspis douglorum Okusu & Normark n. sp. and Hemiberlesia andradae Okusu & Normark n. sp. We provide amendments to the relevant keys, including a new key to New World species of Hemiberlesia Cockerell that lack perivulvar pores. In this context, we treat Abgrallaspis Balachowsky as asubjective synonym of Hemiberlesia, and we transfer its species to Hemiberlesia, except for the following assignments to other genera Affirmaspis flavida (De Lotto), n. comb., Aspidiotus furcillae Brain, rev. comb., Clavaspis perseae (Davidson), n. comb., Diaspidiotus fraxini (McKenzie), n. comb., and Davidsonaspis aguacatae (Evans, Watson, and Miller), n. comb. Davidsonaspis Normark, n. gen. We regard Abgrallaspis azadirachti Ojha and A narainus Dutta & Singh as synonyms of Aonidiella orientalis (Newstead), new synonymy.
The Charipinae material deposited in the United States National Museum of Natural History (Smithsonian Institution) and some specimens deposited in the Canadian National Collection of Insects from the Nearctic region have been revised. In all, 337 specimens have been included in this study and 27 species have been determined. Sixteen species are reported for the first time from the Nearctic region: Alloxysta arcuata (Kieffer, 1902), Alloxysta brevis (Thomson, 1862), Alloxysta castanea (Hartig, 1841), Alloxysta citripes (Thomson, 1862), Alloxysta darci (Girault, 1933), Alloxysta fracticornis (Thomson, 1862), Alloxysta halterata (Thomson, 1862), Alloxysta macrophadna (Hartig, 1841), Alloxysta mullensis (Cameron, 1883), Alloxysta pilipennis (Hartig, 1840), Alloxysta postica (Hartig, 1841), Alloxysta proxima (Belizin, 1962), Alloxysta ramulifera (Thomson, 1862),Phaenoglyphis heterocera (Hartig, 1841), Phaenoglyphis salicis (Cameron, 1883), and Phaenoglyphis stricta (Thomson, 1877). Seven new species are described: Alloxysta buffingtoni Ferrer-Suay & Pujade-Villar n. sp., Alloxysta huberi Ferrer-Suay & Pujade-Villar n. sp., Alloxysta neartica Ferrer-Suay & Pujade-Villar n. sp., Alloxysta texana Ferrer-Suay & Pujade-Villar n. sp., Alloxysta vicenti Ferrer-Suay n. sp., Phaenoglyphis jeffersoni Ferrer-Suay & Pujade-Villar n. sp., and Phaenoglyphis kenaii Ferrer-Suay & Pujade-Villar n. sp. Diagnoses are given for the species newly recorded in this region and their main diagnostic features are present in different plates. New species are completely described and illustrated. A key to identify the Charipinae present in the Nearctic region is also given.
Based on recent reexamination of types, Vesiculentomon rusekiNosek, 1977, differs significantly from Vesiculentomon marshalliRusek, 1974, in composition and shape of maxillary gland, number of anterior setae on metanotum, and shape of foretarsal sensillum t1. A new genus Nosekientomon is erected for V. ruseki. Nosekientomon n. gen. is characterized by three pairs of anterior setae on the metanotum, claviform foretarsal sensillum t1, and a smooth globular vesicle on the calyx of the maxillary gland. Vesiculentomon Rusek has four pairs of anterior setae on the metanotum, baculiform foretarsal sensillum t1, and a large vesicle near the calyx with dense granulation along its narrow proximal part. The original descriptions are corrected and supplemented with new characters, including head chaetotaxy, setal lengths, and porotaxy. A key to world genera of Nipponentominae is provided.
Models were presented that describe the attraction and killing at toxic baits or traps of adult males and females of an insect pest species. These models were used to test the effects of the following factors on ease of control: female monogamy versus polygamy, attraction of only males versus both sexes, initiating mating before versus after responding to baits/traps, the ability of males to mate many times each day versus only once per day, and the existence of a time lag of several days before females can mate versus mating immediately after emergence. The models indicated that mating before trapping or the ability of males to mate many times each day will probably render this control method ineffective. The other factors tested (mating habit and specifics of attraction) had little effect on the efÞciency of trapping males as a control method. We then included age structure and a refractory period for virgin females before they can mate. The models were then made specific to Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) by using parameter values derived from the literature. The results of the models imply that the attraction and killing of large numbers of males is rather ineffective to suppress populations. However, the combination of attracting both males and females can be more effective than attracting either sex alone. The increased attraction of females to methyl eugenol baits that has been observed with the declining presence of males during Male Annihilation Technique campaigns may explain the reported effectiveness against invasive Bactrocera pest species.
We present simple models that describe the factors influencing application of the Sterile Insect Technique (SIT) alone, followed by the factors affecting the integration of the Male Annihilation Technique (MAT) and SIT simultaneously to annihilate wild males and replace them with methyl eugenol (ME)-exposed sterile males that are less responsive to the toxic MAT baits. The removal by MAT of large numbers of males to deprive females of mates is rather ineffective to suppress populations unless a proportion of females are also attracted to baits. When simultaneously implementing SIT and MAT, much less stringent requirements for the annihilation of the wild male population apply and the sterile fly release rate can be reduced to only ≈5% of that when SIT is applied alone. The main determinants of control efficiency are whether a proportion of wild females is attracted to MAT baits, whether most of the wild males respond to the MAT baits before mating, and whether a majority of ME-exposed sterile males do not respond to the baits. However, a high remating frequency in mated females, and the release of only sterile males or both sterile males and females, do not greatly affect the ease of control. We conclude that the simultaneous MAT and SIT application is synergistic and the combination appears to be an extremely powerful control strategy for tephritid fruit fly pests that are attracted to ME.
In wing dimorphic cricket Velarifictorus micado Saussure, group rearing could induce macropters, but rearing density had a nonlinear effect on the incidence of macroptery. Frequency of macropters increased along with rearing density under low-density conditions, but it decreased gradually under high densities, especially for the females. This result indicates that flight ability is required to escape from crowded conditions, but there is a factor that would suppress wing development under high-population density in V. micado. Investigation of body injury showed that incidence of body injury increased along with rearing density, especially for the antenna. Removal of antennas or hindlegs in the penultimate nymphal stage exerted a strong micropterizing effect. These results suggest that brachypterizing effect of high density may be related with body injury. Removed antennas at different instars, brachypterizing effect was only significant in sixth instar (penultimate instar) for males, and sixth and seventh instar (last instar) for females, which suggests that penultimate and last instars may be sensitive stages in winglength development to the effect of body injury in V. micado
The recent introduction of Sirex noctilio F. (Hymenoptera: Siricidae) into North America has raised interest in native siricids and their parasitoids to better understand the potential impact of S. noctilio. In the southeastern United States, we assessed various techniques to capture native siricids and their parasitoids using traps, lures, and trap trees. During 2009–2011, in total, 2,434 wasps were caught including Eriotremex formosanus (Matsumura), Sirex nigricornis (F.), Tremex columba (L.), and Urocerus cressoni (Norton) (Siricidae), and Ibalia leucospoides ensiger Norton (Hymenoptera: Ibaliidae). Traps and trap trees, respectively, captured 14 and 86% of total siricids and hymenopteran parasitoids. Majority of siricids (76%) were caught in Louisiana, where 486 I. l. ensiger (28% parasitism rate) were also reared from trap trees. The Sirex lure alone and Sirex lure with ethanol captured two to five times greater numbers of siricids than unbaited traps. Trap types had no effect on catches of siricids. Fewer siricids were caught in traps baited with ethanol alone than in those baited with other lures in Georgia. We caught three to four times greater numbers of S. nigricornis in traps with fresh pine billets (with foliage) as a lure than traps baited with Sirex lure in Louisiana. More S. nigricornis and I. l. ensiger emerged from cut and felled trap trees created in early rather than late November; these trees also had 14 times greater emergence than those treated with Dicamba. Our results indicate that use of host material and timing may be important for monitoring populations and communities of siricids and their parasitoid species in southern pine forests.
Colorado potato beetle, Leptinotarsa decemlineata (Say), is a major pest of potatoes in North America, Europe, and parts of Asia. It adapts quickly to adverse environments, thereby limiting the longevity of control strategies. Better understanding of variability among geographically isolated populations of this insect might create an opportunity to customize control techniques for local conditions. We investigated insecticide resistance, heat tolerance, and growth potential in six beetle populations collected from different locations in the United States. Significant differences were detected in insecticide resistance, egg mass size, and egg hatchability among the tested populations. Large egg mass size appeared to be offset by lower egg hatchability. We also observed a female-biased sex ratio at least in one of the strains. Population growth rates were different among the strains, but this parameter was not correlated to insecticide resistance. This suggests that using allopatric populations in comparative studies of insecticide resistance might result in confusing effects of geographic isolation with the effects of selection toward resistance.
Larvae of the mosquito Uranotaenia novobscura ryukyuana Tanaka et al., have been reported in tree-holes, bamboo stumps, and artificial water containers. So far, no study has addressed the role that density dependence and weather fluctuations could have played in the abundance of this nonvector mosquito. A year-long study was conducted on the population dynamics of this mosquito using oviposition traps in Okinawa, Japan. Time series analysis and the Ricker population model were used to analyze the association between mosquito density and population growth and fluctuations in relative humidity, temperature, and rainfall. Our results suggest that Ur. novobscura ryukyuana has stable denso-dependent dynamics, which are autonomous from weather fluctuations. Our results were opposite to patterns observed in other subtropical mosquito species, whose population dynamics might be partially driven by weather fluctuations, thus highlighting the diversity of responses that mosquitoes can have to changing environments.
Body size is a key biological trait frequently used to assess fitness. Variation in body size stems from genetic and environmental factors and can have strong affects on reproduction. Here, we quantify narrow-sense heritability of size, fecundity, and sexual size dimorphism in four bark beetle species across two genera: Ips pini (Say), Ips lecontei Swaine, Dendroctonus frontalis Zimmermann, and Dendroctonus brevicomis LeConte. For each species, we conducted rearing experiments pairing parents of large or small size classes and measuring body length of all progeny. There was significant narrow-sense heritability of body size in Ips, but not Dendroctonus. Male parent size in I. pini, I. lecontei, and D. frontalis was positively correlated with progeny production and female parent size was positively correlated with gallery length in I. pini, D. frontalis, and D. brevicomis. All species exhibited sexual size dimorphism (SSD), with males being larger than females (male-biased SSD) in Ips and females larger than males (female-biased SSD) in Dendroctonus. Although mean differences in body length between sexes was small, ≈l–2% for Ips and 2–4% for Dendroctonus, the pioneer sex (first colonizer) was statistically larger than the nonpioneer sex in all species. In addition, the pioneer sex displayed greater phenotypic variation in body length than the nonpioneer sex, and Dendroctonus exhibited greater phenotypic variation in body length than Ips. Differing selection pressures within species and even between sexes likely affect body size and heritability patterns exhibited by bark beetles.
The red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Curculionidae: Scolytinae), is one of the most destructive invasive forest pests in China. Little is known about the biological characteristics of red turpentine beetle. Analysis of the frequency distribution has shown that red turpentine beetle's larvae have five instars with head capsule width 0.64, 0.83, 1.16, 1.45, and 1.99 mm, respectively. The ratio of increase of head capsule width is 1.33, which is consistent with Dyar's rule. The duration of egg, larval, and pupal is ≈10,84, and 10 d, respectively. After its emergence, the callow adult darkens to the typical reddish brown by the time it is ready to leave the tree; beetles begin to "fly out” at the 10th day and continue for 20 d, with the peak flight taking place on the 21st day. Pairs of red turpentine beetles introduced into pine bolts produced 106 offspring. Such basic information is important for developing management strategies to combat this invasive bark beetle in China.
A life table analysis of the 14-spotted ladybird beetle, Propylea quatuordecimpunctata L. (Coleoptera: Coccinellidae), reared on bean aphid, Aphis fabae Scopoli (Hemiptera: Aphididae), was conducted at four constant temperatures (17, 20, 25, and 30 ± 1°C). A temperature dependence in the coccinellid's net reproductive rate, intrinsic rate of increase, finite rate of increase, mean generation time, and doubling time was detected. Estimated values of intrinsic rate of increase were 0.065, 0.095, 0.166, and 0.190 females per female per day at 17, 20, 25, and 30°C, respectively, where Lactin model indicated that the maximum value is achieved at 29.23°C. Females of ≈75, 50, 45, and 20 d old reach their maximum reproductive potential at 17, 20, 25, and 30 ± °C, respectively. In addition, temperature affected the risk of death of immature and female adults, as the survival curves at the examined temperatures were significantly different. The mean survival times decreased from 19.9 to 8.0 d and 123.1 to 33.5 d from 17 to 30°C for entire immature stages and female adults, respectively.
Egg weights of Speyeria (Nymphalidae) species from California were measured to estimate relative sizes of first-instar larvae. First-instar larvae were compared for diapause intensity and for their physiological and behavioral responses to atmospheric humidity and free water. Diapause intensity, measured by number of days between first instar and molt to second instar, ranged from 7.6 d (Speyeria nokomis) to 40.7 d (Speyeria callippe). Among species, diapause intensity was uncorrelated with egg weight, but within three species (S. nokomis, Speyeria mormonia, and Speyeria zerene), diapause intensity was positively correlated to egg weight. There was significant interspecific variability in the desiccation tolerance of diapause larvae to low (11% RH) humidity. The least and most desiccation-tolerant species, respectively, were S. nokomis (LT50= 1.9 d) and S. callippe (LT50 = 13.6 d). Interspecific desiccation tolerance was uncorrelated with egg weight. Larvae of S. nokomis moved from lower to higher humidity within a humidity gradient, whereas larvae of S. callippe did not move toward higher humidity. Desiccated larvae of S. callippe and S. zerene rehydrated by imbibing free water. Exposure of S. callippe and S. zerene larvae to 100% RH in the absence of free water did not result in a body weight increase, but high humidity conditions reduced the rate of water loss.
Lepidopteran erebid Zale phaeograpta (Hampson) has recently been found feeding on blackberry leaves (Rubus sp., cultivar “Tupi”) in two sites of Michoacan, Mexico. The life cycle and several life parameters of this insect, including parasitism, were examined in the laboratory. The egg, larva (seven instars), prepupa, pupa, and adult stages lasted 4.1, 35.9, 3.1, 14.5, and 29.1 d, respectively. Eggs are turquoise blue. The prolegs of first-instar larvae have an enlarged dark area that runs laterally. From second instar onwards, a whitish longitudinal dorsal band is observed along the entire body. Third-instar larvae wear a pair of dorsal protuberances in abdominal segment VIII. The fourth- and fifth-instar larvae are cream-colored, whereas sixth instars are entirely creamy. Pupa is covered with a waxy bloom. The apical margin of the forewings in males has two silvery bands, whereas in females, a dark band is present. Female and male pupae had the same weight (0.5 g) and measured 2.21 and 2.25 cm, respectively. The adult sex ratio of females to males was 1.1:1. The cumulative number of eggs laid by female during her lifetime was 281, with preoviposition and oviposition periods of 9.9 and 7.3 d, respectively. Maximum oviposition occurred 3.9 d after the start of oviposition (87.7 eggs per female). Larvae of Z. phaeograpta were parasitized by Microplitis sp. (Braconidae) (33%) and a currently unidentified Ichneumonidae species (9%), and pupae were parasitized by Brachymeria comitator (Walker) and another unidentified Brachymeria sp. (Chalcididae).
In this study, we investigated the effect of egg rearing temperature and storage time on biological characteristics of the predatory stink bug Podisus nigrispinus (Dallas). In a preliminary experiment, eggs were incubated at 5, 10, 15, and 20°C to examine the effect of rearing temperature on egg development. From this, we found that 15°C was the optimal temperature for egg storage. To examine the effect of storage period on biological characteristics, eggs were stored at 15 ± 1°C for 0 (control), 1, 5, 9, 13, or 17 d, and then maintained at 25°C, allowing us to determine the effect of storage period on incubation period and egg viability. Once nymphs reached the second instar, they were kept in individual petri dishes, and we examined the effect of storage period on stadial length, nymphal viability, and weight of fifth-instar nymphs. Finally, when the nymphs reached the adult phase, we measured the effect of storage period on adult longevity, neonate adult weight, fecundity, and egg hatching success. Our results showed that the storage of eggs at 15 ± 1°C for periods of up to 17 d did not significantly affect most of the biological characteristics analyzed.
We report results of field collections, laboratory rearing, and behavioral observations of tephritids belonging to the tribes Acanthonevrini and Gastrozonini in Malaysia and Thailand. The focus of the study was on general biology, seasonal history, mating, oviposition, larval biology, larval habits, and microhabitats. Host association with bamboo was unequivocally established for 31 species. Adult flies fed on liquids oozing from plants or other sources. Most species developed in the rainy season, when bamboo shoots were available. In Thailand, adult flies gathered along streams in the dry season. Observed sexual behavior patterns appeared to be simple in Gastrozonini, whereas in some Acanthonevrini, the males produced a foamy “nuptial gift,” which was offered to females during courtship. Eggs were laid under sheaths or in injuries to the bamboo surface. The main obstacle to oviposition and penetration of shoots appeared to be the hard culm sheaths.Thelarvae entered feeding substrates via injuries, holes created by other insects, or by squeezing in between culm sheaths and bamboo walls. Larvae of Gastrozonini and Rioxoptilona (Acanthonevrini) fed on living or dead bamboo shoots. Larvae of other Acanthonevrini developed in water-filled internode cavities, scraping particles from walls or collecting them from the water surface. Bamboo growth stages and degree of protection by culm sheaths were used to classify microhabitats. These determined to a large extent which guilds of flies could be found. While larvae of some bamboo tephritids destroyed thin bamboo shoots or branches, most acted as secondary pests and did not cause substantial economic losses.
‘Candidatus Liberibacter solanacearum’ is a pathogen of solanaceous crops (Solanales: Solanaceae) that causes zebra chip disease of potato (Solanum tuberosum L.) and plant dieback in tomato (S. lycopersicum L.) and pepper (Capsicum spp.). This pathogen is vectored by the potato/ tomato psyllid Bactericera cockerelli (Šulc) (Hemiptera: Triozidae), but little is known about the interactions between B. cockerelli and ‘Ca. Liberibacter solanacearum.’ Fluorescence in situ hybridization was used to assess the incidence of ‘Ca. Liberibacter solanacearum’ in the hemolymph, bacteriomes, alimentary canals, and salivary glands of B. cockerelli. Liberibacter was observed in 66% of alimentary canals, 39% of salivary glands, and 40% of bacteriomes dissected from adult psyllids. Compared with adults, the organs of fifth instars appeared less likely to harbor Liberibacter, which was observed in 52% of alimentary canals, 10% of salivary glands, and 6% of bacteriomes dissected from the nymphs. Results of real-time polymerase chain reaction confirmed that fewer fifth instars were infected with Liberibacter compared with adults and indicated that fifth instars were less likely to transmit the pathogen to noninfected host plants. These observations of the localization of ‘Ca. Liberibacter solanacearum’ in the organs and tissues of B. cockerelli adults and nymphs will aid the study of Liberibacter-psyllid interactions and the epidemiology of ‘Ca. Liberibacter solanacearum.’
Lawrence M. Hanks, Peter F. Reagel, Robert F. Mitchell, Joseph C. H. Wong, Linnea R. Meier, Christina A. Silliman, Elizabeth E. Graham, Becca L. Striman, Kenneth P. Robinson, Judith A. Mongold-Diers, Jocelyn G. Millar
We summarize field data on the species composition and seasonal phenology of the community of cerambycid beetles of east central Illinois. Data were drawn from field bioassays conducted during 2009–2012 that tested attraction of adult beetles of diverse species to a variety of synthetic pheromones and host plant volatiles. In total, 34,086 beetles of 114 species were captured, including 48 species from the subfamily Cerambycinae, 41 species from Lamiinae, 19 species from Lepturinae, 2 species from Spondylidinae, and 1 species each from Necydalinae, Parandrinae, Prioninae, and Disteniidae. Most of the best-represented species were attracted to pheromones that were included in field experiments, particularly species that use (R)-3-hydroxyhexan-2-one as a pheromone component. The species captured and their patterns of abundance and seasonal phenology were similar to those in an earlier study conducted in Pennsylvania. The most abundant species identified in both studies included the cerambycines Elaphidion mucronatum (Say), Neoclytus acuminatus acuminatus (F.), Neoclytus mucronatus mucronatus (F.), and Xylotrechus colonus (F.). Cerambycine species became active in an orderly progression from early spring to late fall, whereas most lamiine species were active in the summer and fall, and lepturine species were limited to the summer. Potential cross attraction between some cerambycine species that shared pheromone components may have been averted by differences in seasonal activity period and by minor pheromone components that acted as synergists for conspecifics, antagonists for heterospecifics, or both. These results provide quantitative data on the abundance and seasonal phenology of a large number of species.
Beginning at the third instar, the generalist predator Harpactor angulosus (Lepeletier & Serville) (Reduviidae: Harpactorinae) appears gray in color because of the presence of a whitish particulate wax-like material covering all body segments. In this study, we tested the hypothesis that epidermal cells are responsible for the secretion of the wax-like substance onto the cuticle of H. angulosus. The integument of third instar to the adults of H. angulosus have no external structures specialized in wax secretion, as the wax particles are deposited in a filamentous manner. Third to fourth instars and adult stages have a single-layered epidermis composed of columnar cells. In contrast, lack of wax deposit on the body surface of first and second instars is associated with flattened epidermal cells. The columnar epidermal cells are characterized by a well-developed nucleus, basal cell surface with large infoldings, and a cytoplasm rich in vacuoles. These vacuoles are negative for the presence of carbohydrates and proteins, but strongly positive for the presence of lipids. The structural features of the epidermis and the presence of lipid droplets suggest that lipid metabolism is active within the epidermis from the third instar to the adult of H. angulosus. This is the first record of a glandular epidermis associated with wax secretions in Reduviidae.
Diadromus collaris (Gravenhorst) is an important pupal parasitoid of the diamondback moth, Plutella xylostella (L.), a major insect pest of cruciferous vegetables worldwide. We studied the development of immature stage of D. collaris by dissecting parasitized hosts in the laboratory at 25 ± 1°C and 50–80% relative humidity. The results show that all immature stages complete their development within the same host in 11≈12 d. The egg is hymenopteriform and appears to be anhydropic. There are four larval instars. The first instar is transparent with a sclerotized rectangular chitinous head capsule and distinct mandibles. Head capsule of the second instar turns into more isosceles trapeziumshaped. The third instar looks similar to the second instar but proportionally much larger. The sclerization and dimension of the fourth instar increases significantly. The pupa is a typical exarate form and lacks a cocoon. All life history was fully documented with detailed photomicrographs. Our study will be useful for understanding the physiological interactions between D. collaris and P. xylostella.
The aphid Schlechtendalia chinensis (Bell) induces large single-chamber galls, called horned galls, on the leaf wings (an extending part of the rachis) of Rhus chinensis Miller. Horned galls are initiated when the fundatrix of S. chinensis feeds on the adaxial surface of the leaf wings. We compared the histology of intact versus galled leaf wings during various developmental stages by observing their histomorphology during their chronological development. We found that at the initiation phase, the outer epidermis and opening zone of the galls had many glandular trichomes and that pallisade tissue was replaced by parenchyma cells. The number of glandular trichomes on the outer epidermis was reduced as galls matured. The latex ducts and vascular elements became denser in the inner gall layer, and closer to the gall cavity. Stomata were found on outer epidermis in all gall developmental stages excluding the initiation phase. The effect of the gall-forming aphid on leaf wing ontogenesis is discussed.
Cellulose is the most abundant polymer in the biosphere, and termites are one of the most important metazoan cellulose processors. Termites are a rich source of digestive enzymes such as endo- β-1,4-glucanases, β-glucosidases, xylanases, amylases, pectinases, and laccases, regardless of whether they are termite derived or of microbiotic origin. Molecular identification of the termite's digestive enzyme is a critical initial step toward using termites as bioresources for industrial applications. Here, we report five β-glucosidase sequences obtained from four species of higher termites (Anoplotermes schwarzi Banks, Macrotermes carbonarius (Hagen), Rhynchotermes bulbinasus Scheffrahn, Sphaerotermes sphaerothorax (Sjoestedt)) with differing nutritional biologies. The deduced amino acid sequences indicated that they were most similar to β-glucosidases in the glycosyl hydrolase family 1 (GHF1). All complete coding sequences are 490 amino acids long and contain conserved motifs involved in substrate binding and catalysis. Each sequence was also predicted to be glycosylated at two sites.
Neopedies brunneri (Giglio-Tos, 1894) is a grasshopper belonging to the family Acrididae. This group of insects usually has economic importance in Argentina because of their ability to experience outbreaks, but little is known about them. Insect populations usually differ at the phenotypic level, often according to geographical and environmental variables, which may be a good indicator of some other factors with adaptive significance (such as developmental rate, seasonal resource disposal, and growing seasonal length). The aim of this article is to report the first preliminary analysis of phenotypic variation in natural populations of N. brunneri from central Argentina to study the amount of intra- and interpopulation variation in morphometric traits and their probable association with geographic and climatic variables.Wefound the existence of morphometrical differences among populations and a pattern of geographical variation, with males and females from eastern populations being larger than the ones from the west. Sexual size dimorphism was also detected and found to be correlated to geographical and climactic variation. Moreover, geographic patterns of sexual size dimorphism were determined, helping to clarify differential susceptibility of both sexes to environmental conditions.
Animals must find and select mates in environments that naturally vary in both space and time. Of particular importance for many species are the availability and phenology of host plants for feeding and oviposition sites. Here, we used Murgantia histrionica (Hahn) (Hemiptera: Pentatomidae), a herbivorous insect, to determine mating preferences and success using mating assays and preferences based on odor cues.Wemanipulated the natal and encounter contexts using two different host plants, mustard and broccoli. We found that both the natal host plant and the host plant where insects encountered potential mates significantly affected mating success in this insect. Broccolireared individuals were more likely to mate in general; however, all individuals were more likely to mate when placed in an encounter context of mustard. Using a separate assay, we also found that the natal host plant affected female preference based on odor cues; females preferred the odors of males from the same natal environment that the females experienced as nymphs. In addition, we examined color and body size for host plant effects as both size and color are important factors for many species during mate choice. We found that individuals reared on mustard were larger than those reared on broccoli. However, the proportion of orange color on the dorsum of insects was not significantly affected by the natal host plant. In summary, these results suggest that changes in host plants, as commonly occurs seasonally, may have implications for sexual selection via mate choice.
The sweetpotato weevil Cylas formicarius (F.) (Coleoptera: Brentidae) is one of the most serious insects causing damage to sweetpotatoes in the world. Small populations of these insects can cause severe damage to tubers of the crop. Without proper and effective control, weevil populations are likely to cause a huge or complete loss of sweetpotato production in sweetpotato growing areas. Consequently, there is an urgent need for development of an eco-friendly control method for this weevil. Although some control methods are effective, toxic pesticides applications are detrimental and damaging to our environment. Although pheromone traps are currently being used, no effective control of this weevil was achieved. Therefore, studies were carried out as part of the development of a trapping system for C. formicarius. Previous color-choice field tests have confirmed that C. formicarius preferred red traps over gray, green, brown, blue, white, yellow, or black; light red was more attractive than other shades of red. The current study aimed to know whether C. formicarius behavior changes in indoor conditions. Among the eight colored traps tested in the laboratory, green-colored traps were more effective in attracting C. formicarius than all other colors. It attracted nearly double the number of weevils than standard traps presently being used by growers. Based on these results, it is recommended to use green-colored traps to mass trap weevils (by attracting and killing) from sweetpotatoes grown under indoor (storage) conditions.
In insects, larger males generally have a reproductive advantage over smaller males when competing for mating partners. We examined male reproductive competition together with precopulation and copulation durations, female longevity, and fecundity in the northern corn rootworm in relation to the body size of males and females that were combined for mating. Longevity and fecundity were determined for individually caged, mated females. Of the females in 108 combinations of two males and one female, 35 chose not to mate. Of the females in the 73 combinations that resulted in copulation, 38 were small and 35 were large. The proportions of large and small males that mated did not vary significantly with female size, but large males were more than twice as likely as small males to mate. The precopulation duration did not vary with either male or female size, and no interaction occurred between male and female size for either the precopulation or copulation duration. However, both male and female size affected the duration of copulation, with small males copulating longer than large males and large females copulating longer than small females.Nofemale longevity or egg number differences occurredamongthe body size categories of the mating pairs. The implications of the results for insect resistance management are discussed, considering that the evolution of resistance to certain management strategies, such as resistance to the use of insecticides or of Bt maize, may be accompanied by changes in body size.
Polyphagous solitary parasitoids have difficulty finding mates that can be widely dispersed because of their polyphagous natures. Males of polyphagous species are more likely to rely on compounds characteristic of the female or on sex pheromones to find mates. However, the mating biology of few polyphagous parasitoids has been studied and sex pheromones are known for only a few species of parasitoids altogether. Here we examined the mating biology of the polyphagous parasitoid Itoplectis naranyae Ashmead (Hymenoptera: Ichneumonidae), which attacks a variety of lepidopteran pupae. The existence and timing of emission of female sex pheromones and male response with age were studied in the laboratory. A field test was also conducted to confirm the attractiveness of newly emerged females to wild males over a distance. The results confirmed that volatile compounds are used in the sexual communication in I. naranyae. Females attracted males most strongly shortly after emergence; pupae and older females were much less attractive. Older (30-d-old) males were most responsive to female sex pheromones. Males with prior experience with females responded more strongly than naïve males. The field test showed that traps containing virgin females attracted wild males. These results showed that this solitary polyphagous species uses volatile compounds to find scattered mates at close and moderate ranges. The existence of chemically mediated mate finding suggests that sex pheromone traps may be useful in management of I. naranyae as a biological control agent.
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