Current opinion in insect science最新文献

Insect societies have served as excellent examples for co-ordinated decision-making. The production of sexuals is the most important group decision that social insects face since it affects both direct and indirect fitness. The behavioral processes by which queens are selected have been of particular interest since they are the primary egg layers that enable colony function. As a model system, previous research on honey bee reproduction has focused on swarming behavior and nest site selection. One significant gap in our knowledge of the collective decision-making process over reproduction is how daughter queens simply replace old or failing queens (=supersedure) rather than being reared for the purposes of colony fission (=swarming) or queen loss (=emergency queen rearing). Here, I present a conceptual model that provides a framework for understanding the collective decisions by colonies to supersede their mother queens, as well as provide some key recommendations on future empirical work.

Communication systems require coordination between senders and receivers; therefore, understanding how novel signals arise is challenging. Intraspecific geographic variation in signaling provides an opportunity to investigate the factors that shape signal evolution. Facial signals in Polistes paper wasps provide an interesting case study for the causes and consequences of geographic variation in signaling systems. Two species of paper wasps, Polistes dominula and Polistes fuscatus, have been well studied for their facial patterns that signal quality and individual identity, respectively. Remarkably, whether or not facial patterns are used as signals at all appears to vary geographically in both species. The relative evidence for the roles of phenotypic plasticity versus genetic differentiation is discussed. Future research directions that leverage geographic variation in Polistes hold promise to substantially contribute to understanding the links between signals and behavior, as well as the evolution of cognition.

The past decade of social insect research has seen rapid development in automated behavioral tracking and molecular profiling of the nervous system, two distinct but complementary lines of inquiry into phenotypic variation across individuals, colonies, populations, and species. These experimental strategies have developed largely in parallel, as automated tracking generates a continuous stream of behavioral data, while, in contrast, ‘omics-based profiling provides a single ‘snapshot’ of the brain. Better integration of these approaches applied to studying variation in social behavior will reveal the underlying genetic and neurobiological mechanisms that shape the evolution and diversification of social life. In this review, we discuss relevant advances in both fields and propose new strategies to better elucidate the molecular and behavioral innovations that generate social life.

Insect cuticle exhibits a wide array of micro- and nano-structures in terms of size, form, and function. However, the investigation of cellular mechanisms of morphogenesis has centered around a small number of structure types and organisms. The recent expansion of the taxa studied, and subsequent discoveries prompt us to revisit well-known models, like the one for bristle morphogenesis. In addition, common themes are emerging in the morphogenesis of cuticular structures, such as the polyploidy of precursor cells, the role of pigments and cuticular proteins in controlling chitin deposition in space and time, and the role of the apical extracellular matrix in defining the shape of the developing structure. Understanding how these structures are synthesized in biological systems holds promise for bioinspired design.

Declining insect populations are concerning, given the numerous ecosystem services provided by insects. Here, we examine yet another threat to global insect populations — nutrient dilution, the reduction in noncarbon essential nutrients in plant tissues. The rise of atmospheric CO₂, and subsequent ‘global greening’, is a major driver of nutrient dilution. As plant nutrient concentrations are already low compared to animal tissues, further reductions can be detrimental to herbivore fitness, resulting in increased development times, smaller intraspecific body sizes, reduced reproduction, and reduced population sizes. By altering herbivore populations and traits, nutrient dilution can ramify up trophic levels. Conservation of Earth’s biodiversity will require not just protection of habitat, but reductions in anthropogenic alterations to biogeochemical cycles, including the carbon cycle.

MicroRNAs are ubiquitous in the genomes of metazoans. Since their discovery during the late 20th century, our understanding of these small, noncoding RNAs has grown rapidly. However, there are still many unknowns about the functional significance of miRNAs — especially in non-model insects. Here I discuss the accumulating evidence that microRNAs are part of gene regulatory networks that determine not only the developmental outcome but also mediate transitions between stages and alternative developmental pathways. During the last 20 years, researchers have published a multitude of profiling studies that describe changes in miRNAs that may be important for development and catalog potential targets. Proof-of-principle studies document phenotypic changes that occur when candidate genes and/or miRNAs are inhibited or overexpressed. Studies that use both of these approaches, along with methods for confirming miRNA–mRNA interaction, demonstrate the necessary roles for miRNAs within gene networks. Together, all of these types of studies provide essential clues for understanding the function of miRNAs in the developmental toolbox.

The composition and dynamics of ecological communities are complex because of the presence of large numbers of organisms, belonging to many different species, each with their own evolutionary history, and their numerous interactions. The construction and analysis of trophic webs summarize interactions across trophic levels and link community structure to properties such as ecosystem services. We focus on agroecological communities, which may be simpler than natural communities but nonetheless present considerable challenges to describe and understand. We review the characteristics and study of communities comprised of plants, phytophagous insects, and insect parasitoids with particular regard to the maintenance of sustainable agroecological communities and ecosystem services, especially biological pest control. We are constrained to largely overlook other members of these communities, such as hyperparasitoids, predators, parasites, and microbes. We draw chiefly on recent literature while acknowledging the importance of many advances made during the immediately preceding decades. Trophic web construction and analysis can greatly improve the understanding of the role and impact of herbivores and natural enemies in agroecological communities and the various species interactions, such as apparent competition, which assists biocontrol strategies. The study of trophic webs also helps in predicting community ecology consequences of externally driven changes to agroecosystems.

Fipronil, a pesticide widely used to control agricultural and household insect pests, blocks insect GABA_A and glutamate (GluCl) ionotropic receptors, resulting in uncontrolled hyperexcitation and paralysis that eventually leads to death. The use of fipronil is controversial because unintentional exposure to this compound may contribute to the ongoing global decline of insect pollinator populations. Although the sublethal effects of fipronil have been linked to aberrant behavior and impaired olfactory learning in insects, the precise mechanisms involved in these responses remain unclear. In this article, we highlight recent studies that have investigated the interaction among different pathways involved in the ability of fipronil to modulate insect behavior, with particular emphasis on the role of GABAergic neurotransmission in fine-tuning the integration of sensorial responses and insect behavior. Recent findings suggest that fipronil can also cause functional alterations that affect synaptic organization and the availability of metal ions in the brain.