We assessed the functional and numerical responses of Trichogramma brassicae Bezdenko under long-term rearing (45 generations, G5-G45) on eggs of a common factitious host, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae). Under such long-term mass rearing, the function response of this parasitoid shifted from Type III (from G5 to G20) toType II (from G25 to G45).The maximum attack rate (T/Th) (33.62 hosts/day) and the shortest handling time (0.7138 ± 0.0272 h) were recorded in G5. Also, G45 had the lowest attack rate (21.67 hosts/day) and longest handling time (1.1076 ± 0.0689 h). The handling time increased gradually over the generations (P _reg <0.01, R² = 0.903). The number of eggs laid by the parasitoid increased significantly with increased host density, but reached a plateau at very high densities. While no significant differences in daily parasitism were observed over 45 generations at densities of 2, 4, 8, and 16 available host eggs per wasp, there were significant differences in parasitism at host densities of 32, 64, and 128 eggs per wasp. T. brassicae females were more active and foraged more frequently in earlier generations (G5 to G20), which allowed wasps to parasitize more E. kuehniella eggs compared to later generations. Also, continuous mass rearing of T. brassicae negatively affected foraging behavior and the quality of wasps after G20. However, rejuvenation of the colony by adding field-collected parasitoids or rearing wasps on more suitable factitious hosts is strongly recommended to lower the negative effects of long-term mass rearing on quality of this parasitoid.

The purpose of this study was to determine the structure of the community and seasonality of the Cerambycidae family in the tropical deciduous forest (TDF) of San Andrés de la Cal, Tepoztlán in Morelos, Mexico. Following a year of systematic collections, and with the addition of data obtained from breeding chambers and sporadic collections, 155 species, 91 genera, 35 tribes, and 4 subfamilies were recorded. Thirty-three of these species, >21% are new records for the state of Morelos. Sample coverage was 97% and, according to the Chao 1 richness estimator, we found 80% of the species present in the study area. Greater species richness, abundance, and diversity were found during the rainy season, which generates a significant difference between seasons. The ordering of faunal similarities between months indicated a marked seasonality in the composition. The data suggest that the diversity of TDF insects is not completely known (i.e., new records were found), but comprises a diverse community, composed of a high proportion (78%) of rare species. Our findings reinforce the need to continue documenting insect diversity in TDF, especially considering that this is among the least protected of the ecosystems, and one that is negatively affected to a greater degree by anthropogenic activities and climate change.

El propósito de este estudio fue conocer la estructura de la comunidad de la familia Cerambycidae del bosque tropical caducifolio (BTC) de San Andrés de la Cal,Tepoztlán, Morelos, México. Después de un año de recolectas sistemáticas, además de datos adicionales de cámaras de cría y recolectas esporádicas, se registraron 155 especies, 91 géneros, 35 tribus y 4 subfamilias. Treinta y tres especies (>21%) son nuevos registros para el estado de Morelos. La cobertura de muestra fue del 97% y según el estimador de riqueza Chao 1, el 80% de las especies del área de estudio están representadas. La mayor riqueza, abundancia y diversidad de especies ocurrió durante la temporada de lluvias y el ordenamiento entre meses indicó una marcada estacionalidad. La estructura de la comunidad refleja una gran diversidad, compuesta por una alta proporción (78%) de especies raras. Los datos muestran que la diversidad de insectos en el BTC es alta y que los datos de distribución están incompletos (e. g. nuevos registros) lo que refuerza la necesidad de seguir documentándolo, especialmente considerando que este ecosistema se encuentra entre los menos protegidos y con mayor riesgo de desaparecer por la presión de las actividades antropogénicas y el cambio climático.

Sexual dimorphism in body size has been observed for many insect species. However, whether dimorphism influences the flight performance for closely related insects or between the genders of conspecifics has seldom been examined. Wing loading (i.e., body mass/total wing area, WL = M/A) is an important indicator of flight efficiency and maneuverability. We examined the potential for sexual dimorphism and interspecific differences in wing loading for three cicada species (Cryptotympana atrata, Meimuna mongolica, and Platypleura kaempferi) and tested the hypothesis that females have higher WLs than males possibly because they must carry the extra weight of eggs. There were significant dimorphic differences in body mass and WL for each of the three species. However, there were no significant dimorphic differences in total wing area for C. atrata and M. mongolica, whereas P. kaempferi females had larger mean total wing area than males. Among the three cicada species, males had lower WLs (and by inference, greater maneuverability) than females. In addition, the M vs. A scaling exponent (i.e., α) was numerically significantly greater than unity (i.e., α > 1). Thus, WL should scale with respect to M with α > 1, which accounts for why females have a larger WL than males. We interpret these results to indicate that gender dimorphism in body size and flight performance likely reflect selection on traits affecting reproductive success that, in turn, likely depend on flight maneuverability.

In insects, insulin signaling plays a pivotal role in the regulation of growth, metabolism, reproduction, and aging. Revealing the regulatory roles of insulin signaling in natural enemy insects is helpful for developing artificial approaches to promote reproduction. In this study, the expression of four insulin-like peptides (ILPs) in female adults of the natural predator Chrysopa pallens was analyzed by quantitative real-time-polymerase chain reaction (qRT-PCR) and their functions were investigated by RNA interference (RNAi). C. pallens ILP1 (CpILP1) and C. pallens ILP4 (CpILP4) showed a gradual increase in mRNA levels from early adult stages to later stages. However, C. pallens ILP2 (CpILP2) and C. pallens ILP3 (CpILP3) had an opposite expression curve with a high transcript level at the beginning of the adult stage and a gradual reduction thereafter. All four CpILPs showed high expression levels in the ovary, but CpILP2 transcripts were also abundant in fat bodies. Disruption of CpILP1 and CpILP2 expression by RNAi-mediated knockdown strikingly suppressed ovarian development and reduced C. pallens vitellogenin gene 1 (CpVg1) transcripts. Depletion of CpILP3 transcripts did not significantly decrease ovariole number but drastically reduced CpVg1 expression. Interference with the expression of CpILP4 significantly inhibited ovarian development but did not suppress CpVg1 expression. All gene knockdowns failed to dramatically impair total fecundity and egg quality.These data suggest that the four C. pallens ILPs are involved in reproductive signaling at different degrees.

Temperature extremes often limit animal distributions. Whereas some poikilotherms (e.g., winged insects) can escape local thermal extremes, many less vagile organisms (e.g., insect larvae and arthropods with limited dispersal ability) are at the mercy of local microenvironmental conditions. Here, we quantified the thermal tolerance of an abundant, endemic, Nearctic millipede (Euryurus leachii), and explored the effects of seasonality, mass, and sex on its critical thermal maxima (CT_max). We also measured the thermal microenvironments of dead wood representing different decay classes. Overall, the mean CT_max for this species was ca. 40.5°C. Mass and sex had no effect on millipede CT_max. However, the mean CT_max for millipedes collected in the fall was 0.6°C higher than for individuals collected in the spring. An exposed dry log representing one common microhabitat for E. leachii readily warmed to temperatures exceeding its CT_max.The results suggest that CT_max is a seasonally plastic trait in E. leachii and that microclimatic conditions potentially limit the local distribution of this species. With habitat fragmentation and climate change contributing to warmer temperatures in forested systems, understanding the responses of detritivores like E. leachii can help predict potential shifts in community composition and ecosystem processes.