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The monogeneric family Brachypsectridae is redescribed based on adults and larvae, and distribution, biology, and ideas on the phylogenetic relationships are summarized. Presently available data from both adults and larvae support previous conclusions that the family is a basal member of the Elateroidea. The four described species of Brachypsectra LeConte are reviewed. Brachypsectra moronei Branham sp. n. is described from the Dominican amber; larvae of Brachypsectra fulva LeConte, Brachypsectra lampyroides Blair, and an unnamed species from Australia are described; and keys are given to males of all described species and to known larvae. In addition, a lectotype and paratypes are designated for the six recognized syntypes of Brachypsectra lampyroidesBlair, 1930.
Species of Dioryctria Zeller (Lepidoptera: Pyralidae) are important pests of conifers, particularly in seed orchards, and accurate species identification is needed for effective monitoring and control. Variable forewing morphology and lack of species-specific genitalic features hinder identification, prompting the search for additional diagnostic characters. Mitochondrial DNA (mtDNA) sequences from the cytochrome c oxidase I and II genes (COI and COII) were obtained from specimens collected at lights, pheromone traps, and host plants in the Pacific Northwest, focusing on a U.S. Forest Service seed orchard in Chico, CA. A 475-bp fragment of COI was used to identify eight distinct genetic lineages from 180 Dioryctria specimens, and these were identified as eight described species. Comparisons among mtDNA variation, adult morphology, larval host association, and pheromone attraction were used to assign individuals to species groups and to identify diagnostic characters for species identification. A 2.3-kb fragment of COI-COII was sequenced for 14 specimens to increase resolution of phylogenetic relationships. Species groups were well resolved using both the 475-bp and “DNA barcode” subsets of the 2.3-kb sequences, with the 475-bp fragment generally showing lower divergences. The zimmermani and ponderosae species groups were sister groups and had similar male genitalic morphology and larval feeding habits. The pentictonella group was sister to the zimmermaniponderosae group clade, and all species have raised scales and a Pinus sp. larval host (where known). Combining molecular characters with morphological and behavioral characters improved identification of Dioryctria species and supported previous species group relationships.
A new species of ground cricket in the genus Allonemobius (Hebard) is described from the southwestern United States. Like many singing Orthoptera, this species is morphologically cryptic and most easily distinguished from related species by using molecular characters and male calling song traits. We describe Allonemobius shalontaki as a new species and present data suggesting its reproductive isolation from congeneric species. Allonemobius shalontaki exhibits a unique male calling song and possesses a distinct allozyme genotype. Additionally, we present an electrophoretic key to the genus and propose phylogenetic relationships among species.
The brachypterous grasshopper Podisma sapporensis Shiraki (Orthoptera: Acrididae) consists of two major chromosomal races with different sex chromosome systems. In the X0/XX race, the diploid number of chromosomes is 2n = 23 (X0) in males and 2n = 24 (XX) in females. In the XY/XX race, the diploid number is 2n = 22 (XY) in males and 2n = 22 (XX) in females, owing to Robertsonian fusion between an autosome and the X chromosome. The X0/XX and XY/XX races are allopatrically distributed, and each race contains geographical populations characterized by different chromosomal inversions. A previous hypothesis suggested that the XY/XX race was derived from the X0/XX race. To test this hypothesis, we examined mitochondrial DNA (mtDNA) sequence variation in two regions (cytochrome oxidase subunit II and 16S ribosomal DNA) among 29 P. sapporensis individuals representing five X0/XX and 12 XY/XX populations. The maximum parsimony tree of mtDNA indicated that neither of the two chromosomal races was monophyletic. Northern populations of XY/XX race did not join a clade consisting of more southern XY/XX populations but were included in a clade consisting of X0/XX populations. On the basis of these results, we propose two hypotheses for the differentiation between the northern and southern XY/XX populations. First, the XY/XX karyotype may have occurred more than once. Second, introgression of mtDNA may have occurred across adjacent populations possessing different karyotypes.
Termite surveys of 33 islands of the Bahamas and Turks and Caicos (BATC) archipelago yielded 3,533 colony samples from 593 sites. Twenty-seven species from three families and 12 genera were recorded as follows: Cryptotermes brevis (Walker), Cr. cavifrons Banks, Cr. cymatofrons Scheffrahn and Křeček, Cr. bracketti n. sp., Incisitermes bequaerti (Snyder), I. incisus (Silvestri), I. milleri (Emerson), I. rhyzophorae Hernández, I. schwarzi (Banks), I. snyderi (Light), Neotermes castaneus (Burmeister), Ne. jouteli (Banks), Ne. luykxi Nickle and Collins, Ne. mona Banks, Procryptotermes corniceps (Snyder), and Pr. hesperus Scheffrahn and Křeček (Kalotermitidae); Coptotermes gestroi Wasmann, Heterotermes cardini (Snyder), H. sp., Prorhinotermes simplex Hagen, and Reticulitermes flavipes Koller (Rhinotermitidae); and Anoplotermes bahamensis n. sp., A. inopinatus n. sp., Nasutitermes corniger (Motschulsky), Na. rippertii Rambur, Parvitermes brooksi (Snyder), and Termes hispaniolae Banks (Termitidae). Of these species, three species are known only from the Bahamas, whereas 22 have larger regional indigenous ranges that include Cuba, Florida, or Hispaniola and beyond. Recent exotic immigrations for two of the regional indigenous species cannot be excluded. Three species are nonindigenous pests of known recent immigration. Identification keys based on the soldier (or soldierless worker) and the winged imago are provided along with species distributions by island. Cr. bracketti, known only from San Salvador Island, Bahamas, is described from the soldier and imago. Two soldierless species, Anoplotermes bahamensis n. sp. and Anoplotermes inopinatus n. sp., from the central Bahamas are described from the imago and worker. The imago of Pa. brooksi is described for the first time. Mutually exclusive distributions were recorded for the following groups: Cr. bracketti/Cr. Cymatofrons Cr. cavifrons, Ne. mona/Ne. jouteli, Pr. corniceps/Pr. hesperus, R. flavipes/H. cardini H. sp., and Na. corniger/Na. rippertii. All termites found on the Turks and Caicos also occur in parts of the Bahamas except for the likely exotic H. sp., and the exotic Co. gestroi. Present-day distributions of indigenous termite species are related to two primary factors: dry land connections of the BATC during low sea level stands of the late Pleistocene and the proximity of these emergent lands to the faunal sources of Florida, Cuba, and Hispaniola. Flotsam containing mated reproductives or whole colonies are propagules for overwater dispersal by termites.
The presence of the ant subfamily Myrmeciinae is established in the Early Eocene (Ypresian) Okanagan Highlands localities of Horsefly River, Falkland, McAbee (British Columbia, Canada) and Republic (Washington state, United States) and in the Mo-clay Ølst and Fur Formations (Denmark). Nine new species in four new genera (three orthotaxa: Ypresiomyrma n. gen., Avitomyrmex n. gen., and Macabeemyrma n. gen.; one parataxon: Myrmeciites n. gen.) are described. Seven are placed in the Myrmeciinae: Ypresiomyrma orbiculata n. sp., Ypresiomyrma bartletti n. sp., Avitomyrmex elongatus n. sp., Avitomyrmex mastax n. sp., Avitomyrmex systenus n. sp., Macabeemyrma ovata n. sp., and Myrmeciites herculeanus n. sp.; two further species are tentatively placed in the subfamily, Myrmeciites (?) tabanifluviensis n. sp. from Horsefly River, and Myrmeciites (?) goliath n. sp. from McAbee. Two further myrmeciine ants are treated as Myrmeciites incertae sedis, a male from Falkland and a female (worker or queen) from Republic. Pachycondyla rebekkae Rust and Andersen, from the earliest Ypresian of Denmark, is reassigned to the genus Ypresiomyrma, within the Myrmeciinae. The fossil record indicates a northern hemisphere origin of the subfamily. The presence of Ypresiomyrma in Denmark and British Columbia further reflects the well-documented Paleogene cross-North Atlantic distributions of biota. The known fossil record of the Myrmeciinae is restricted to the Eocene.
Female alates of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), infected with Thelohania solenopsae Knell, Allen, and Hazard (Microsporidia: Thelohaniidae) were found to be significantly less likely to be among the early alates to initiate a mating flight. If a flight was initiated, the infected females were significantly more likely to initiate the flight later in comparison with uninfected alates. In addition, many infected female alates seemed not to fly as a significantly greater proportion of the remaining females. Furthermore, infected females exhibited a significantly reduced body weight and a significantly reduced lipid titer, in comparison with uninfected individuals. However, there was no difference between the infected and uninfected alates in the amount of soluble protein. These results suggest that the low-weight, late flying-infected females may be less likely to reach a male mating swarm and less likely to outcompete uninfected females in mating and dispersing. Last, if mated or not, upon landing, the infected females may less likely have the needed energy to initiate a colony.
To evaluate its importance as a possible reservoir host of tephritid pests (Diptera) of cultivated fruit, we sampled fruit of the exotic invasive Solanum mauritianum Scop. in various sites throughout its range in central and western Kenya. Tephritids were reared from S. mauritianum wherever the plant was found, except at the highest altitudes (2,200–2,500 m). Ceratitis anonae Graham and Ceratitis fasciventris (Bezzi) were reared from fruit sampled in western Kenya, whereas the latter and Ceratitis rosa Karsch were reared from fruit found in central Kenya. In Kakamega Forest in western Kenya, C. anonae was reared from S. mauritianum year-round, whereas C. fasciventris was present in only 52.6% of the collections at this locality. A host shift by C. fasciventris onto S. mauritianum during the drier months from November to January is suggested as an explanation for the observed change in relative rates of infestation of S. mauritianum by the two Ceratitis species in western Kenya. In Nairobi (central Kenya), C. fasciventris was reared from fruit collected year-round. C. rosa was not recovered until the last of 17 Nairobi collections. In Kenya, S. mauritianum maintains year-round populations of tephritid pests available to attack cultivated fruit. S. mauritianum should be considered a noxious invasive pest in Kenya, and efforts to eradicate or control it should be made wherever it occurs.
The commercial apple (Malus spp.) orchard ecosystem in Quebec has a diverse fauna of predacious mites. A systematic 2-yr survey showed Amblyseius fallacis (Garman), Typhlodromus caudiglans Schuster (Acari: Phytoseiidae), and Agistemus fleschneri Summers (Acari: Stigmaeidae) to be the most abundant species. Other phytoseiids, Typhlodromus conspicuous (Garman), Typhlodromus herbertae Chant, Typhlodromus longipilus Nesbitt, Typhlodromus bakeri (Garman), Typhlodromus pyri Scheuten, Amblyseius okanagensis (Chant), and Amblyseius finlandicus (Oudemans), were found in low numbers. Two of these species, A. finlandicus and T. conspicuus, were identified for the first time in Quebec. Other occasional species included Anystis baccarum (L.) (Acari: Anystidae) and Balaustium sp. (Acari: Erythraeidae). Tetranychid mite numbers were always less than two mites per leaf throughout the study, and none of the commercial orchards required an acaricide treatment. A notable aspect of this study was that seasonal totals for A. fleschneri and A. fallacis decreased 7.3- and 42.2-fold, respectively, whereas T. caudiglans increased 9.1-fold from 1999 to 2000. Possible mechanisms for these changes, including variations in winter mortality, competition for food, and intraguild predation are discussed.
Few studies have evaluated the relative importance of bottom-up regulation for the population dynamics of mutualism. To address this, we tested the hypothesis that host plant quality affects the strength of the mutualism between Publilia concava (Say) (Hemiptera: Membracidae) treehoppers feeding on Solidago altissima L. and ants. P. concava is a phloem-feeding treehopper that excretes a sugary waste product called honeydew. Ants collect this honeydew as a food resource, and treehoppers benefit both directly (e.g., feeding facilitation) and indirectly (e.g., protection from predators). We evaluated the effect of host plant quality on both the direct and indirect effects of this mutualism by using a factorial design that manipulated N–P–K fertilizer level and ant presence. For the experiment that focused on the direct effects of ant tending, both body size and survivorship were monitored. For the experiment that included the indirect effects of ant tending, only survivorship was monitored. Both host plant quality and ant tending increased the performance (survivorship and size) of Publilia treehoppers. However, we find no support for the hypothesis that host plant quality influences the strength of the mutualism in this system—there was no significant interaction between ant tending and fertilization for any measure of treehopper performance considered. We suggest that this result is explained by the independence of per capita tending levels with both host plant quality and treehopper density in this experiment.
Tetraleurodes perseae Nakahara (Hemiptera: Aleyrodidae) is an exotic whitefly in California that is a minor pest of avocados, Persea americana Miller (Lauraceae). Field monitoring over a 4.5-yr period (1997–2002) in a commercial avocado orchard in southern California indicated that T. perseae is probably univoltine, and adult densities show single distinct peaks each year around August. The only hymenopteran parasitoid found attacking T. perseae in California was an aphelinid, Cales noacki Howard, and parasitism over February–April each year ranged from 30 to 100%. Partial life tables constructed from cohorts of T. perseae in the field indicated that survivorship from settled first and second instars to emerged adult whiteflies ranged from 34 to 37%. There were no significant differences in marginal mortality rates by life stage for whitefly cohorts enclosed in sealed mesh bags, open mesh bags, or on unenclosed avocado leaves. Survivorship curves constructed from field phenology data indicated that average egg-to-adult survivorship was around 3.5%, which is substantially lower than that suggested from the life table analyses. Laboratory studies conducted at 25°C on excised avocado leaves indicated that ≈43–46 d is needed by T. perseae to complete development from egg to adult. Demographic analyses of laboratory data indicate that T. perseae has a high reproductive potential with net reproductive rate and intrinsic rate of increase estimates being 21.15 ± 1.39 and 0.07 ± 0.001, respectively.
Balaustium spp. mites are noted for their quickness, red color, population bursts, and ubiquity. Water balance characteristics of adults were assessed to determine their primary source of water to gain insight into the biology and physiology of these poorly studied mites. Characteristics of this mite show that it is xeric adapted, featuring a 71% body water content, 39% dehydration tolerance limit, and a modest water loss rate of 2% h−1. This species is unable to absorb water vapor from atmospheric air which is unusual for mites. This is illustrated by net water losses at water vapor activities close to saturation, failure to maintain the uptake after first day passive gains, and no detectable salt accumulation around the base of the mouthparts in scanning electron micrographs. Thus, enhanced water conservation enables this mite to withstand desiccation, and their aggressive predatory life style has apparently not necessitated evolution of an active uptake mechanism for absorption of water vapor for this mite that obtains most of its water from feeding.
Kapala (Hymenoptera: Eucharitidae) are among the most frequently collected chalcidoid wasps from the Neotropics, but general information about their host plants, behavior, and life history is scarce. A new species, Kapala izapa n. sp., parasitizing Ectatomma ruidum Roger (Hymenoptera: Formicidae), is described from Chiapas, Mexico, with a general account of its biology. Field observations on the behavior of adults of Kapala iridicolor (Cameron), which also attack E. ruidum, Gnamptogenys regularis Mayr, Gnamptogenys sulcata (Fr. Smith), Gnamptogenys striatula Mayr, and Pachycondyla stigma (F.) (Hymenoptera: Formicidae), are included. Immature stages of Kapala izapa n. sp. follow the general morphology and behavior described for other eucharitids known to attack Ectatomminae and Ponerinae. More than one parasitoid can complete development on a single host larva. K. iridicolor females were observed laying masses of eggs on undeveloped flower buds of Melampodium divaricatum (L.C. Richard) D.C. (Asteraceae). Extrafloral nectaries of this plant are visited by several insects, including predatory foraging worker ants of E. ruidum. Dissection of recently emerged females of K. iridicolor yielded ≈4,500 fully developed eggs.
We present molecular data for an endosymbiont of the insect family Pentatomidae, located in the gastric caeca of Nezara viridula (L.) (Hemiptera: Pentatomidae) stink bugs. Restriction fragment length polymorphism and polymerase chain reaction analysis suggest that this bacterium is consistently present in caeca of N. viridula from a variety of geographic locations. The bacterium is present in different midgut sections in nymphs versus adults. The bacterium also was detected on eggshells after nymphs had hatched but not in ovarioles, suggesting oral rather than transovarial transmission. Surface sterilization of egg masses generated aposymbiotic insects. Aposymbiotic individuals reached the adult stage, females laid viable eggs, and the offspring remained aposymbiotic in the following generation. No clear fitness decrease was observed in aposymbiotic individuals over two generations. Phylogenetic analysis of a partial 16S rRNA data set with 21 Gammaproteobacteria suggested the inadequacy of neighbor-joining and maximum parsimony models to account for homoplasy apparent in a molecular data set, including a range of insect endosymbionts. Maximum likelihood-based analysis suggests that the N. viridula endosymbiont is closely related to a caeca-associated symbiont found in another stink bug family (Plataspidae). The high AT content of the symbiont’s 16S rRNA in relation to other insect endosymbionts, its location in the midgut of the host insect, oral transmission, and survival of aposymbiotic individuals suggest this symbiosis may be recently established.
Plant parts are commonly used as oviposition substrates for mass rearing of Orius spp., but this system does not permit the isolation of clean intact eggs for use as standards in a yolk protein enzyme-linked immunosorbent assay (ELISA). An oviposition substrate was devised for O. insidiosus by forming water-filled domes from Parafilm-M. Eggs were deposited through the Parafilm skin into water where they remained viable for at least 24 h. Eggs were extracted from the domes and collected onto black filter paper and then used to prepare lyophilized yolk protein as a quantitative standard in ELISA tests. In no-choice tests, O. insidiosus females oviposited 5.86 eggs per female per d into ‘Blue Lake’ green beans, Phaseolus vulgaris L., and 3.06 eggs into water-filled domes. Hatch rates did not significantly differ, although optimal moisture was critical. In a choice test, O. insidiosus females preferred beans to domes (4.02 versus 0.03 eggs per female per 18 h). Females preferred to oviposit into the walls of the major groove of green beans and often oviposited around the lower perimeter of water-filled domes. Lyophilized protein from eggs collected in water-filled domes was successfully and replicably used in the yolk protein ELISA after compensating for reduced immunological activity with a correction factor. Parafilm-covered water-filled domes are therefore useful for collection of eggs for use in the yolk protein ELISA and for other applications that require viable eggs. These domes also may lead to discovery of the phytochemical and physical factors that are responsible for choice of a host plant and its parts for oviposition.
During the first day of embryogenesis in firebrat, Thermobia domestica (Packard) (Zygentoma: Lepismatidae), energids (nuclei surrounded by a thin layer of nonmembraned cytoplasm) migrate toward the periplasm. Some of them are dispersed in the periplasm, whereas others remain inside the yolk. As the first syncytial blastoderm is formed, the oolemma invaginates deeply into the yolk forming numerous folds. These folds surround the energids that are settled in the periplasm. The cellular blastoderm, formed at the end of cleavage, remains thin. These cellularization events are described at the ultrastructural level. Our previous studies dealt with midgut epithelium formation. Our current results indicate that the same mechanism of cellularization occurs in both processes in this primitive wingless insect. The similarities between the mode of cellularization of the blastoderm and the midgut epithelium are discussed.
Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) consists of a species complex with various degrees of reproductive compatibility between biotypes. One mechanism known to result in reproductive isolation among sexually reproducing animals is mate recognition. Whiteflies have an elaborate courtship and mating behavior, and it is well known that individuals of some biotypes in the B. tabaci species complex will court individuals of other biotypes, but they will not mate. In this study, we determined specific courtship and mating behaviors of B. tabaci biotype B (Bemisia argentifolii Bellows & Perring). Four distinct phases in the courtship and mating cascade were identified, and we describe these phases and report their durations. We compared our findings with previously reported mating behaviors of two other whiteflies, B. tabaci biotype A, and Trialeurodes vaporariorum (Westwood). These comparisons identified both similarities and differences in the behaviors of the three whiteflies, particularly in the extent and position of antennal drumming, male abdominal undulation, and wing and body position during copulation. Body pushing behavior, characterized for B. tabaci biotype A and T. vaporariorum, was not present for B. argentifolii. The similarities between whiteflies may represent evolutionarily conserved behaviors, resulting in courtships between reproductively incompatible whiteflies. Conversely, differences in behaviors may contribute to prezygotic reproductive isolation among biotypes. From our studies, we propose that the discrimination of signals sent and received from courting whiteflies becomes more intense with each successive phase in the courtship cascade.
Understanding the principles that govern the mating behavior of insects that are the target of areawide integrated pest management (AW-IPM) programs by using the sterile insect technique (SIT) is a prerequisite to ensure optimal efficiency of such programs. Models were constructed to assess the effect of mating preference of insects, which display a female- or male-choice mating system, on the efficiency of SIT programs that release males only or programs that release both sexes. The model on preferential mating indicated that in a male choice mating system [e.g., screwworm, Cochliomyia hominivorax (Coquerel)], overcoming the discrimination of wild males against mating with sterile females would require a doubling of the number of sterile males compared with male-only releases. The model on female choice was incapable of distinguishing between reduced sterile male competitiveness and female preference for wild males and implied, in addition, that the release of both sexes and male-only releases required the same sterile to wild male overflooding ratio. Operational SIT projects have, however, shown a significant benefit with male-only releases against insects which have a female-choice mating system [e.g., Mediterranean fruit fly, Ceratitis capitata (Wiedemann)], and models were constructed to assess the potential effect of sterile female presence or absence on some parameters, i.e., reduced sterile sperm quantity with remating, reduced sterile sperm quality with aging and incomplete redistribution of the sterile males with the wild insects. The model suggests that in all three cases, male-only releases result in relatively more efficient sterile insects compared with programs releasing both sexes. The results of the models are discussed in relation to data available from operational screwworm and Mediterranean fruit fly AW-IPM programs with an SIT component.
The characterization of courtship behavior in two sympatric and synchronic leafroller species, Choristoneura rosaceana (Harris) and Pandemis pyrusana Kearfott, indicated that only pheromone permeated airflow was needed as a releaser to initiate the male mating sequence. Mating ethograms demonstrate that males of both species perform six observable, discrete, and homogeneous steps: 1) wing fanning; 2) first contact; 3) male next to female (mostly in C. rosaceana), head-to-head (only P. pyrusana); 4) curled abdomen; 5) genitalia engagement; and 6) end-to-end position (mating). The sequences were highly stereotypic, suggesting that once a male starts the mating sequence, the rest of the steps will most likely follow. First contact with the female was a preprogrammed response, not requiring further cues. Copulation was more likely when the female remained stationary after first contact. Unsuccessful mating sequences were frequent during the study because females escaped by walking away, turning around, or jumping away. Because courtship behavior is a mechanism to select sexual partners, it is possible to hypothesize that responses resulting in an unsuccessful mating (assumed to be rejection) validate this mechanism. The mating sequence of C. rosaceana best matches the simple courtship behavior model, whereas the sequence in P. pyrusana resembles an interactive courtship. Overall results indicate that courtship behavior in both species would be compatible with attracticide (i.e., sex pheromone insecticide) technology that requires direct contact between males and the pheromone source.
The early emergence (protandry) of males is common in a variety of insects. Most studies to date have explained protandry as an adaptive reproductive strategy. Sexual selection favors males that emerge before females because this maximizes the number of encounters with females. However, protandry may be a side effect of female-biased sexual size dimorphism (SSD) because larger females need a longer developmental time than males. Despite the plausibility of the adaptive protandry hypothesis, determining whether protandry is adaptive or incidental is difficult because size and developmental time are interdependent. Female-biased SSD is a common trend among insects and has been most frequently attributed to fecundity selection favoring large females. Reticulitermes speratus Kolbe alates showed significant SSD with female alates that were consistently heavier than male alates. A significant tendency was observed that SSD increased as body size increased among the colonies. A sexual difference in eclosion timing should be disadvantageous in this termite species because male and female alates perform swarming (nuptial flight) synchronously. Alates of an early emerging sex must use reserve nutrition while they wait for eclosion of the other sex in the colony. Nevertheless, significant protandry was found in R. speratus, and this tendency was detected even at the molt of the earlier nymphal stage. Therefore, the early emergence of males in this termite species is clearly incidental protandry due to the SSD. The occurrence of incidental protandry or protogyny as a side effect of sexual size dimorphism may be as common as adaptive protandry.
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