Embioptera display variability in egg-handling as part of their defense against natural enemies. Because species living in tropical regions experience potentially higher risks of predation than those in temperate climes, we hypothesized that variable risk might explain this variability. We used actual evapotranspiration (AET) rates as a stand-in for climate, region, and potential interactions with natural enemies. We predicted that more complex investments, such as coating individual eggs, organizing them, and topping the cluster with thick silk would co-occur with greater predation threats in tropical regions, scored as higher AET. We predicted that simpler organization of eggs would occur where predator risk would be lower, as in temperate regions (lower AET). We used phylogenetic comparative methods to assess whether more complex egg handling behavior correlated with high AET scores. We quantified five traits of egg handling from field and laboratory evidence for 29 species from habitats ranging from low to high AET. Initial pGLS and pGLM analyses showed a weak effect of AET on parental care index. Upon exclusion of three exotic species spread artificially by trade and collected outside their native ranges, we found strong effects of predation threat in both pGLS and pGLM analyses. These analyses revealed that species that experience potentially greater predation threats exhibited behaviors that corresponded to more complex handling and organization of eggs by the mother. These results align nicely with analyses that also detected that additional lines of defense of eggs typify the behavior of tropical species of other primitively social arthropods.

Spiders are notoriously solitary and cannibalistic, with instances of colonial or social lifestyles in only about 50-60, or ∼0.1% of 50,000 described species. Population analyses indicate that most colonies consist of multiple cohorts formed by close relatives.Territorial social spiders facultatively form colonies by interlinking individual webs, but further cooperation is infrequent, and only among juveniles or (rarely) females. In spiders therefore, aggregations of males outside of the male-male competition context has been unknown. Here, we report on a discovery of a kite spider from Madagascar that exhibits unique colonies. We found colonies of the newly described araneid Isoxya manangona n. sp. formed by up to 41 interconnected, single-cohort adult female webs with up to 38 adult males aggregating on a central, single, nonsticky line. With males resting tightly together, we found no evidence for male-male aggression. Genetic analyses from RAD sequencing suggest that most colonies consist of unrelated individuals. Furthermore, genetic variability of males was somewhat less than that of females. Single cohort colonies made up purely of adults, and peaceful male aggregations, have not previously been observed in spiders. Although direct behavioral observations are preliminary, we speculate based on the available evidence that these colonies may represent a novel and first case of lekking in spiders.

The diversification of alpine species has been modulated by their climatic niches interacting with changing climatic conditions. The relative roles of climatic niche conservatism promoting geographical speciation and of climatic niche diversification are poorly understood in diverse temperate groups. Here, we investigate the climatic niche evolution in a species rich butterfly genus, Erebia (Dalman, 1816). This Holarctic cold-dwelling genus reaches the highest diversity in European mountains. We generated a nearly complete molecular phylogeny and modeled the climatic niche evolution using geo-referenced occurrence records. We reconstructed the evolution of the climatic niche and tested how the species' climatic niche width changes across the occupied climate gradient and compared two main Erebia clades, the European and the Asian clade. We further explored climatic niche overlaps among species. Our analyses revealed that the evolution of Erebia has been shaped by climatic niche conservatism, supported by a strong phylogenetic signal and niche overlap in sister species, likely promoting allopatric speciation. The European and the Asian clades evolved their climatic niches toward different local optima. In addition, species in the European clade have narrower niches compared to the Asian clade. Contrasts among the clades may be related to regional climate differences, with lower climate seasonality in Europe compared to Central Asia favoring the evolution of narrower niches. Further, adaptive divergence could appear in other traits, such as habitat use, which can be reflected by narrower climatic niches detected in the European clade. Our study extends knowledge about the complexity of evolutionary drivers in temperate insects.

Xenos vesparum of the highly specialized Strepsiptera is a new insect model in the context of host-parasite relationships.The endoparasitic female and male secondary larvae were studied using µCT, 3D-reconstructions, histology, and photomicrography.The infectious primary larva is followed by a trophic and endoparasitic secondary larval stage. In contrast to immature stages of other holometabolous groups, the second instar increases dramatically in size. Compound eyes and external wing anlagen are present in male larvae before the pupal stage. In contrast to the females, the brain of males bears well-developed optic neuropils and retinula cells are present.The cephalothorax is comparatively simple in the female larvae, yet distinctly more complex than in the adult, where most muscles are reduced. Large testes are present in male larvae and numerous oocytes in the females, but they are still immature.The larval features are discussed in the context of holometabolous development and heterochronic processes. Unique features of Strepsiptera are the early differentiation of the sexes and the occurrence of compound eyes and external wing anlagen in male secondary larvae. The phylogenetic position of Strepsiptera suggests that this is a secondary feature and thus an autapomorphy. To address mature females of Stylopidia as neotenic adults is an oversimplification.They display a mosaic pattern of paedomorphic characters such as features of the nervous system and the presence of stemmata, but also non-paedomorphic structures, such as the spiracles.