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Three hundred eighty-two freshly oviposited gypsy moth, Lymantria dispar (L.), egg masses from two laboratory strains (fertile and F1-sterile) and one wild strain were subjected to seven temperature regimes. Egg hatch was monitored daily in each egg mass until egg hatch was completed. The hatch pattern of each strain in each temperature regime was described by a cumulative distribution of percentage of total egg hatch, and distributions were compared statistically. Egg hatch distributions differed significantly in all but three of the 21 comparisons. However, cumulative egg hatch milestones of 5, 50, and 95% were reached by the F1-sterile egg masses <1, 2, and 4 d later, respectively, than either the laboratory fertile or wild strains. These differences are small relative to the ≈8 mo spent in the egg stage, and they should not invalidate the use of F1-sterile egg masses as sentinel eggs where the risk of establishment with fertile eggs is deemed too great.
Two new species of the edaphic genus Hesperotyphlus Coiffait are described from the Natural Park of Arribes del Duero in western Spain. Based on characteristic of its labrum and aedeagus, H. mendezferrini n. sp. belongs to the H. besucheti Coiffait species group, whereas H. zarazagai n. sp. is included in the H. beirensis Coiffait species group. Male and female genitalia are described and illustrated for both new species, and the relations of each taxon to its respective species groups are discussed. Keys for the groups of species of H. besucheti and H. beirensis are provided. The two new species were found in leaf litter of Mediterranean deciduous forests composed of Quercus pyrenaica Willdenow or Q. faginea Lamarck (Fagaceae), and they occurred together in one of the sampling localities.
RESUMEN. Se describen dos especies del género edáfico Hesperotyphlus Coiffait, procedentes del Parque Natural de los Arribes del Duero (oeste de España). Debido a las características de su labro y edeago, H. mendezferrini n. sp. pertenece al grupo de especies de H. besucheti Coiffait, mientras que H. zarazagai n. sp. se incluye en el grupo de H. beirensis Coiffait. Se describen e ilustran las genitalia masculina y femenina de los dos nuevos taxones y se discuten las relaciones con las especies de sus respectivos grupos. Se aportan claves para las especies de los grupos de H. besucheti y H. beirensis. Las dos especies nuevas se encontraron en hojarasca de bosques mediterráneos caducifolios compuestos de Quercus pyrenaica Willdenow o Q. faginea Lamarck [Fagaceae], y viven juntas en una de las localidades de muestreo.
A new genus, Pachacutia n. gen., of large, rare Andean ithomiine butterflies is described and characterized, containing four species. Two species and their constituent subspecies and synonyms (Ithomia cleomella Hewitson, Ithomia mantura Hewitson, Ithomia honrathi Srnka, and Dircenna barrettii Dannatt) are transferred to Pachacutia from Godyris Boisduval (n. comb.). Two additional species are described from southern Ecuador (Pachacutia baroni n. sp.) and Bolivia (Pachacutia germaini n. sp.), and a new subspecies, Pachacutia mantura joroni n. ssp., is described from Peru. Pachacutia is a member of a clade containing otherwise small, often abundant lowland forest ithomiines, including Mcclungia R.M. Fox, Brevioleria Lamas, and some species of Hypoleria Godman & Salvin. A comparative phylogenetic analysis showed Pachacutia species to be related as follows: (baroni (mantura (cleomellagermaini))). A key for identification of all taxa, and illustrations of male and female genitalia for all species and adult specimens of all taxa, are presented, and the taxonomy and natural history of all taxa are discussed.
A new species of Pseudacteon phorid fly, Pseudacteon calderensis (Diptera: Phoridae), is described from females attacking worker ants of Solenopsis interrupta Santschi in Salta and Jujuy provinces, northwestern Argentina. P. calderensis differs from almost all other South American Pseudacteon species by the structure of the female ovipositor. This new species is morphologically similar to Pseudacteon borgmeieri Schmitz, but it differs slightly in the shape of the apex of the ovipositor and differs strongly because of the absence of large and stout ventral hairs under the ovipositor.
In the Great Lakes region, Rhagoletis zephyria Snow (Diptera: Tephritidae) infests snowberries, Symphoricarpos albus variety laevigatus (Fern.) Blake, a western North American native plant that has been introduced widely into eastern North America. These R. zephyria infestations have been hypothesized to be the result of flies that were introduced into eastern North America along with their host plants. In its native range, R. zephyria infests S. albus variety laevigatus, but it infests a related host, Symphoricarpos occidentalis Hook., in the northern Great Plains. Knowledge of the natural geographic and host ranges of R. zephyria is important. R. zephyria is a sibling species of the apple maggot, Rhagoletis pomonella (Walsh), and aspects of R. zephyria biology can be applied to work on speciation mechanisms. Additionally, the possible co-occurrence of morphologically similar R. zephyria and R. pomonella in apple (Malus spp.)-growing regions complicates the positive identification of trap-caught flies in the R. pomonella species group. Here, we examine the hypothesis that R. zephyria in the Great Lakes region has been introduced. Collections of R. zephyria yielded new state/provincial records in Idaho, South Dakota, Nebraska, Wisconsin, Michigan, Pennsylvania, New York, Massachusetts, Maine, and Ontario and Quebec, Canada, and a new host record, S. albus variety albus, which is native to eastern North America. Finding R. zephyria infesting native host plants in the eastern United States leads us to hypothesize that R. zephyria infestations in the Great Lakes region may not be the result of recent (historical) introductions of R. zephyria, but rather they may represent native R. zephyria populations.
We describe the cicada Okanagana georgi, sp. n. along with notes on its biology and acoustic behavior. The species is restricted along Schnebly Hill Road in Coconino County, AZ. It is associated with Arizona cypress, Cupressus arizonica Greene, in the riparian habitat of the canyon. The species is most active in the late morning and late afternoon. The song is a continuous train of pulses produced at a rate of 106.92 Hz and an intensity of 97.4 dB. Thermal responses (minimum flight temperature 19.76°C, maximum voluntary tolerance temperature 33.13°C, heat torpor 43.00°C) are related to the habitat and observed behavior. A key is provided to the species of Okanagana Distant found in Arizona.
Drosophila gouveai Tidon-Sklorz & Sene and Drosophila antonietae Tidon-Sklorz & Sene (Diptera: Drosophilidae) are two cactophilic sibling species that belong to the Drosophila buzzatii cluster, which comprises seven species living in South America. D. gouveai uses the decaying stems of Cactaceae of the genus Pilosocereus as breeding sites, whereas D. antonietae is mainly associated with Cereus hildmannianus K. Schum. In this article, we investigate the effect that growing in alternative host cacti may have on fitness-related traits, developmental time and viability, relevant for species that live in ephemeral resources. Both species were reared in seminatural media prepared with fermenting tissues of either Pilosocereus machrisis Y. Dawson or C. hildmannianus. Our results show that the specific differences in the traits analyzed are host dependent. Overall, both species performed very well in P. machrisis, whereas survival in C. hildmannianus differed dramatically between species. The viability of D. antonietae was lower than in P. machrisis, whereas D. gouveai barely survived in C. hildmannianus. The results are discussed in relation to biogeographic, morphological, and molecular evidence, and they stress the need to assess the relative significance of host plant use in diversification of the D. buzzatii cluster.
The cactus moth, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae), was reported in Florida in 1989, and it is expanding its geographical range to threaten Opuntia cactus (Cactaceae) in the southwestern United States, into Mexico, where it is an important economic crop. Laboratory life history studies were conducted at 18, 22, 26, 30, and 34°C to understand cactus moth biology and to develop strategies for control. Duration of immature stages was generally longest at 18°C, declining significantly at 22°C, and shortest at 26, 30, and 34°C. Total immature developmental time from eggs to pupae was ≈180 d at 18°C, 116 at 22°C, and ranged from 65 to 72 d at 26–34°C. Developmental rate for egg-to-pupal stages was estimated using the logistic equation, rate = 0.0165/(1 (T/20.7093)−5.8823). Percentage survival of immatures was usually lowest at the temperature extremes tested (18 and 34°C), but they did not differ between the sexes. Estimated lower developmental threshold temperature was 13.3°C, resulting in estimated degree-days for development from ≈845 at 18°C to 1,387 at 34°C. In general, pupal weights declined with increasing temperature, and they were always lower in males than in females. Female adult survivorship was longest at 18°C, and shortest at 34°C, with the other treatments clustered between the temperature extremes. The highest reproductive values were found at 30°C, which indicates an approximate optimal temperature. Net reproductive rate (R0), gross reproductive rate (GRR), generation time (T), intrinsic rate of increase (r), finite rate of increase (λ), and doubling time (DT) were 43.68 ♀/♀, 44.02 ♀/♀, 67.14 d, 0.0562 ♀/♀/d, 1.058 ♀/♀/d, and 12.33 d, respectively. An oviposition rate surface describing mean oviposition rate as a function of time and temperature was, eggs = (−11.241 0.854T) d exp (−0.020Td). Given the life history characteristics found in this study and other studies, cost-effective pest management strategies against C. cactorum are discussed.
Although a brown rot fungus, Gloeophyllum trabeum (Pers.) Murrill, has been shown to be attractive and beneficial to subterranean termites, including Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), no research has been conducted to determine whether the association is mutualistic. We first investigated whether the fungus could be spread by C. formosanus, because this would represent an obvious benefit to the fungus. We found that Formosan subterranean termites did not spread G. trabeum, rather they suppressed its growth. To further investigate this phenomenon, wood chips were inoculated with G. trabeum, and fungal growth was measured in treatments with termites or without termites (controls). A significant suppression of fungus growth was found only in treatments where termites were present. This antagonistic interaction between the termites and fungus was further investigated by placing wood chips from the termite treatments on potato dextrose yeast agar medium to determine G. trabeum survivorship. Although G. trabeum did not grow, many green-spored fungi developed, including Aspergillus flavus Link and Trichoderma spp. We hypothesize that these green-spored fungi are carried by termites and that they may play a role in suppressing the growth of G. trabeum.
Twenty-two species of Pseudacteon flies (Diptera: Phoridae) are known to attack fire ants (Solenopsis spp.) in Argentina, Brazil, Bolivia, and Paraguay, but none are known in Chile. Surveys were conducted in central Chile and at similar latitudes in western Argentina to detect the presence of fire ants and parasitoid flies and to determine their relationship. Flies and fire ants were much more common and abundant in Argentina. In total, 100 colonies of four fire ant species were found at 63.6% of the sites surveyed. In contrast, only six colonies of one species, Solenopsis gayi (Spinola), were found at 4.7% of the sites surveyed in Chile. Our survey includes the first record of five parasitic fly species in central western Argentina and a new host, Solenopsis quinquecuspis Forel. The large form of Pseudacteon obtusus Borgmeier was found attacking S. gayi in Chile, which is the first record in that country, and the first record on this host species. The southern-most and western-most records were established for fire ant-decapitating flies. Mitochondrial DNA (mtDNA) indicates that S. gayi is genetically closer to the Argentine fire ants (saevissima-group) than the North American S. geminata-group. However, S. gayi venom alkaloid composition is similar to S. geminata-group, whereas cuticular hydrocarbon composition has characteristics of both groups. Analysis of mtDNA from the collected flies supports the monophyly of P. obtusus and suggests that the Chilean population is similar to populations in eastern Argentina. The presence of P. obtusus in Chile could be explained by immigrant parasitized fire ant species from Argentina or by an accidental introduction.
The northern corn rootworm, Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae) is an agricultural pest that ranges from the eastern Dakotas to Kansas and east to the Atlantic coast. The endosymbiotic bacteria Wolbachia has been detected in northern corn rootworm populations from east of the Mississippi River. Using the Wolbachia 16S rDNA, ftsZ and wsp genes a boundary was identified in central Illinois, between infected and uninfected populations with the infected populations found to the east of the boundary. Sequences of portions of the Wolbachia ftsZ and wsp genes have been obtained from four geographic locations of northern corn rootworm. Within infected northern corn rootworm populations, two strains have been detected. The 1,058-bp ftsZ sequences from northern corn rootworm indicate that both strains belong to the Wolbachia supergroup A. NCR Type 1 Wolbachia was found from eastern Illinois to Pennsylvania. NCR Type 2 Wolbachia occurs in central Illinois. The ≈600-bp wsp sequences from the two strains are also dramatically different. Strain differences in restriction fragment length polymorphism patterns of the Wolbachia-specific amplicons were used to determine the distribution of the strains. The boundary between these two strains of Wolbachia in native populations of northern corn rootworm correlates with a previously observed mitochondrial DNA genetic boundary in eastern Illinois, suggesting that the two Wolbachia strains are incompatible and little if any introgression occurs between the two infected populations. The results demonstrate that Wolbachia can influence the genetics of a major insect pest over a wide geographic area and that it may be driving reproductive isolation between populations of northern corn rootworm.
To understand the evolution of parasitism, a fundamental question is what influences the distribution of globally distributed parasites among different hosts. Reticulitermes termites often harbor brown fungal balls, called “termite balls,” alongside their eggs. The termite ball was identified as the sclerotium of a parasitic corticioid fungus, an undescribed species of genus Fibularhizoctonia, which mimics termite eggs physically and chemically so as to be protected in termite nests. This phenomenon has been found for Reticulitermes species in Japan and the United States, but not all the Reticulitermes species in these countries have termite balls. To identify factors influencing the distribution of termite balls among their host species, we conducted wide-range sampling in the temperate zone and in subtropical zones in Japan and Taiwan. We also conducted phylogenetic analyses of termite ball fungi and their host termites based on molecular data. In Amami-Oshima Island, R. amamianus Morimoto colonies had termite balls only in temperate highland regions, but no termite balls were found in its subtropical lowland region. The introduced termite R. kanmonensis Takematsu had termite balls as well as sympatrically occurring R. speratus (Kolbe). The termite ball fungi isolated from these two species showed no significant molecular difference, suggesting no host race formation. Phylogenetic analysis showed that R. kanmonensis in Japan did not diverge from R. flaviceps (Oshima), which has no termite balls, in Taiwan. Analyses of termite ball distribution among nine Reticulitermes species suggested that climate is the most important factor restricting the distribution of the termite ball fungi.
The four species of Dasineura Rondani previously reported from goldenrods in North America were revisited, resulting in the synonymy of two species and the redescription of diagnostic characters of adults and galls. Dasineura folliculi Felt is reported from Solidago rugosa Miller and S. gigantea Aiton, and D. carbonaria Felt is reported from Euthamia graminifolia (L.) Nuttall. Both species induce simple leaf-cluster galls on shoot tips of their relative hosts. Dasineura folliculi completes for to five generations, and D. carbonaria completes at least two generations between May and October. Emergence rates were relatively low; they ranged from 36 to 51%, suggesting a large proportion of the larval population does not pupate and instead enters diapause in the ground. D. folliculi galls were attacked by five species of parasitic wasps and by inquilinous and predatory gall midges and caterpillars. Levels of attack by parasitoids increased, whereas levels of attack by inquilines decreased, as the season progressed. Field data and greenhouse experiments indicated that both Dasineura species exhibit monogeny, whereby females produce unisexual broods. Galls resulting from a single oviposition event exclusively yielded single-sex adults, whereas 7–33% of field-collected galls yielded adults of both sexes, suggesting they contained the progeny of more than one female. Gall sex ratios differed between generations of D. folliculi on S. rugosa but not on S. gigantea.
Insect reproduction is typically spread out in time and space, making estimates of lifetime reproductive success quite difficult under natural field conditions. Such estimates are, however, critical to providing rigorous tests of theory for reproductive behavior. One approach to circumventing this problem is to study insects whose lifetime reproduction is compressed in space and time, and whose ovarian dynamics (oogenesis, oosorption, and oviposition) are simplified. We investigated the gall midge Rhopalomyia californica Felt (Diptera: Cecidomyiidae) as a possible candidate for an herbivore with such a simplified pattern of lifetime reproduction. We demonstrate here that R. californica matures all of its eggs before adult eclosion (it is strictly proovigenic), and it does not resorb eggs, even when deprived of oviposition sites. Observational and experimental studies in the field demonstrate that this midge typically completes its entire lifetime reproduction in a single day: females usually emerge at dawn, mate, and after a posteclosion period of resting, they initiate a sustained period of active oviposition during which most eggs are laid over a 4–5-h period. Mean longevity of adult females is very short, consistently <1 d and only 5–6 h on clear and warm days. Two key aspects of senescence are experimentally demonstrated: an increase in mortality rates and a decrease in oviposition rates with age. The life history traits associated with the ephemeral adult stage of R. californica are consistent with a syndrome that has been characterized recently for many proovigenic herbivorous and parasitic insects. Proovigenic species, including R. californica, may be particularly valuable as model systems for studies of lifetime reproductive success in nature.
Larval rearing of Bactrocera invadens Drew, Tsuruta & White (Diptera: Tephritidae) on artificial diet is described. The adaptation process for this insect, when moved from whole mango, Mangifera indica L., fruit rearing to artificial diet based on wheat bran, took between three and five generations to reach the plateau of quality control parameters observed for rearing the insect on whole mango fruit. Small-scale rearing on wheat, Triticum aestivum L.-, or carrot, Daucus corata-based diet revealed significantly higher pupal recovery for flies reared on the wheat-based artificial diet (68.8%) compared with the carrot-based diet (58.2%). Weekly production of puparia was 3,966.8 on wheat- and 3,012.1 on carrot-based diet. Other quality control parameters, including pupal weight, adult emergence, flight ability, fecundity, and fertility did not differ significantly between the two artificial rearing media tested.
Xylanase and β-xylosidase activities were assayed for each gut region of field-collected Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae) workers, as well as those kept on eight diets. Five diets were formulated, consisting of varying ratios of cellulose and xylan. The remaining three diets, red oak (Quercus spp.), pine (Pinus spp.), and filter paper, were intended to represent probable food sources in the field. Xylanase and β-xylosidase activities were primarily located in the hindgut (>92% total xylanase activity, ≈50–75% total β-xylosidase activity), providing strong evidence that xylan digestion is mainly carried out by hindgut symbionts in R. flavipes workers. Among the formulated diets, both xylanase and β-xylosidase activities were significantly higher in termites kept on 20 and 40% xylan than in termites kept on 0 and 5% xylan. Among the field diets, both xylanase and β-xylosidase total activities were highest on the oak diet, the diet with the highest xylan content, and lowest on the paper diet, a diet without xylan. Both activities were evident in termites fed on the 100% cellulose diet and the paper diet, in spite of the lack of xylan in these diets. The presence of xylanolytic activity on xylan-free diets indicates the presence of xylanolytic symbionts that can survive on a diet of pure cellulose. Xylanolytic activities in the R. flavipes colony changed to accommodate the xylan content of their diet, most likely by changes in the hindgut symbiont communities. This flexibility allows a termite colony to efficiently use a variety of wood species and wood-derived materials.
In opilionids, scanning electron microscopy (SEM) studies are necessary to identify the characters of taxonomic and systematic importance. Such studies are needed especially for understanding the functional anatomy and morphology of opilionids. In Turkey, Phalangium opilio L., Phalangium pareissi Roewer, Phalangium punctipes (L. Koch), Phalangium savignyi Audouin, and Phalangium strandi Nosek are known. There are no SEM studies on P. opilio. In this study, cuticular setae, hairs, and denticles on the segments of legs, pedipalpus, and chelicerae of P. opilio are described. Also, the description and SEM pictures of the dorsal integument and articulations, chelicerae, pedipalpus, and legs of the male specimens are given. Some of these structures will probably prove to be of diagnostic value for P. opilio.
The pecan weevil, Curculio caryae (Horn) (Coleoptera: Curculionidae), is an obligate nut feeder of all hickory (Carya spp.) and a key pest of the pecan, Carya illinoinensis Koch. This study investigates population genetic structure of the pecan weevil. Gene flow and genetic variation was estimated for 90 pecan weevil specimens sampled within the range Carya occurring in the United States. Cladistic and nested clade analyses, as well as an analysis of molecular variance of mitochondrial DNA cytochrome oxidase I were performed. Six-hundred and forty equally parsimonious trees of 31 haplotypes demonstrated high genetic diversity across all pecan weevil samples, and significant regional subdivision. Three clades recovered in the parsimony and nested clade analyses were strongly associated with western, central, and eastern localities sampled within the range of C. caryae. The current distribution of C. caryae and population structure were explained by past glaciation events. The data indicate C. caryae diverged from its sister species, Curculio nasicus (Say), ≈4.3 million years before present (mybp). Lineage divergence between the western and eastern populations occurred during the Pleistocene (≈1.1 million mybp), and a more recent divergence occurred between C. caryae populations east and west of the Appalachian mountain range (870,000 yr ago). Haplotypes were segregated by region, but further sampling is necessary to test for gene flow among these regions.
Males of Sphenarium purpurascens (Charpentier) (Orthoptera: Pyrgomorphidae) can spend up to 18 d mounting a female and mating repeatedly during this period. However, both females and males are polygamous. In this study, we assessed the potential benefits of multiple matings for females, with the same male or with different males. Furthermore, we evaluated the capacity of the male to assess the risk of sperm competition. The fecundity of females mated repeatedly with a male was not affected by the number of matings, but it increased by having prolonged matings. Moreover, polyandry did not increase fecundity of females. Females mated with one male produced more eggs and heavier clutch than females mated with two males. We also found that the second male that mated a female spent more time mating and guarding her than the first male, suggesting that male investment may change according to the risk of sperm competition.
We investigated several aspects of the nesting biology of Epicharis metatarsalis Friese (Hymenoptera: Apidae) in a lowland wet-forest of northeastern Costa Rica. Five large aggregations were found 30–100 m from larger rivers at the La Selva Biological Station. The relatively short nesting season, from May to August, indicates that E. metatarsalis is probably univoltine. Four nests were excavated to study nest architecture, and five brood cells from three different nests were analyzed for pollen composition. Additionally, we analyzed pollen loads from 33 females returning from pollen-collecting trips, and we observed male patrolling behavior. The canopy tree Apeiba membranacea Spruce ex Benth (Tiliaceae) was found to be the principal pollen source, representing an average proportion of 98.5% of each pollen load and 93.4% of the larval provisions. The brood cell with the lowest proportion of A. membranacea pollen contained 89.3% A. membranacea pollen, which was 98.5% by relative volume. Pollen of Byrsonima crispa A. Juss. (Malpighiaceae) was the second most frequently encountered pollen with average proportions of 1.3 and 4.9% in pollen loads and larval provisions, respectively. E. metatarsalis can thus be considered oligolectic. The E. metatarsalis nesting season coincides with the relatively short flowering season of B. crispa, perhaps because of the importance of B. crispa as a source of oils rather than nectar.
The braconid parasitoid Fopius arisanus (Sonan) (Hymenoptera: Braconidae) is a candidate for augmentative biological control of tephritid fruit flies. In the Puna district of Hawaii Island, F. arisanus parasitized 41–72% of oriental fruit flies, Bactrocera dorsalis (Hendel), in wild common guava, Psidium guajava L.; strawberry guava, Psidium cattleianum Sabine; and tropical almond, Terminalia catappa L. In commercial papaya, Carica papaya L., in the same region, parasitism was only 22% in tree-collected fruit and 3% in ground-collected fruit. The low level of parasitism in papaya suggests that wild parasitoids may not track the host flies well in commercial fruit and that augmentative parasitoid releases could potentially increase parasitism and thus suppress host fly populations in this habitat. The very low parasitism in ground-collected papaya suggests that F. arisanus may avoid foraging on ground fruit. Field cage experiments support this hypothesis. Numbers of females observed on tree fruit were two-fold higher than on ground fruit in small cages and 4–6-fold higher in large cages. In an experiment conducted in a papaya orchard, sentinel fruit was placed within the canopy, on the trunk, or on the ground. Parasitism was significantly higher in the canopy-placed fruit in only one of three trials. This variable response to ground fruit in the field suggests that augmentative parasitoid releases may have a significant, albeit reduced, effect on host populations under conditions of poor sanitation.
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