Search results for "Insect"

Sex-allocation conflict and sexual selection throughout the lifespan of eusocial colonies.

2018

AbstractModels of sex allocation conflict are central to evolutionary biology but have mostly assumed static decisions, where resource allocation strategies are constant over colony lifespan. Here, we develop a model to study how the evolution of dynamic resource allocation strategies is affected by the queen-worker conflict in annual eusocial insects. We demonstrate that the time of dispersal of sexuals affects the sex allocation ratio through sexual selection on males. Furthermore, our model provides three predictions that depart from established results of classic static allocation models. First, we find that the queen wins the sex allocation conflict, while the workers determine the max…

Characterization of the resistance to Vip3Aa in Helicoverpa armigera from Australia and the role of midgut processing and receptor binding.

2016

AbstractCrops expressing genes from Bacillus thuringiensis (Bt crops) are among the most successful technologies developed for the control of pests but the evolution of resistance to them remains a challenge. Insect resistant cotton and maize expressing the Bt Vip3Aa protein were recently commercialized, though not yet in Australia. We found that, although relatively high, the frequency of alleles for resistance to Vip3Aa in field populations of H. armigera in Australia did not increase over the past four seasons until 2014/15. Three new isofemale lines were determined to be allelic with previously isolated lines, suggesting that they belong to one common gene and this mechanism is relative…

Covariation and phenotypic integration in chemical communication displays: biosynthetic constraints and eco-evolutionary implications

2018

Chemical communication is ubiquitous. The identification of conserved structural elements in visual and acoustic communication is well established, but comparable information on chemical communication displays (CCDs) is lacking. We assessed the phenotypic integration of CCDs in a meta‐analysis to characterize patterns of covariation in CCDs and identified functional or biosynthetically constrained modules. Poorly integrated plant CCDs (i.e. low covariation between scent compounds) support the notion that plants often utilize one or few key compounds to repel antagonists or to attract pollinators and enemies of herbivores. Animal CCDs (mostly insect pheromones) were usually more integrated t…

2017

The endosymbiotic bacterium Wolbachia is the most widespread bacteria in insects, yet the ecology of novel acquisitions in natural host populations is poorly understood. Using temporal data separated by 12 years, I tested the hypothesis that immigration of a parasitoid wasp led to transmission of its Wolbachia strain to its dipteran host, resulting in double-strain infection, and I used geographic and community surveys to explore the history of transmission in fly and parasitoid. Double infection in the fly host was present before immigration of the parasitoid. Equal prevalence of double infection in males and females, constant prevalence before and after immigration in two regions, and inc…

The origins of northern European Autographa gamma individuals evaluated using hydrogen stable isotopes

2018

Natural Occurrence of Secondary Bacterial Symbionts in Aphids from Tunisia, with a Focus on Genus Hyalopterus

2018

Aphids (Hemiptera: Aphididae) can harbor two types of bacterial symbionts. In addition to the obligate endosymbiont Buchnera aphidicola Munson, Baumann and Kinsey 1991 (Enterobacteriales: Enterobacteriaceae), several facultative symbiotic bacteria, called secondary (S) symbionts, have been identified among many important pest aphid species. To determine interpopulational diversity of S-symbionts, we carried out a survey in a total of 18 populations of six aphid species collected from six localities in Tunisia, by performing a diagnostic polymerase chain reaction analysis of partial 16S-23S rRNA operon sequences. While 61.7% of individuals contained only Buchnera, three S-symbionts were foun…

Microbial symbionts expanding or constraining abiotic niche space in insects

2020

In addition to their well-studied contributions to their host’s nutrition, digestion, and defense, microbial symbionts of insects are increasingly found to affect their host’s response toward abiotic stressors. In particular, symbiotic microbes can reduce or enhance tolerance to temperature extremes, improve desiccation resistance by aiding cuticle biosynthesis and sclerotization, and detoxify heavy metals. As such, individual symbionts or microbial communities can expand or constrain the abiotic niche space of their host and determine its adaptability to fluctuating environments. In light of the increasing impact of humans on climate and environment, a better understanding of host-microbe …

Temporal variations in symbiotic hindgut protist community of the subterranean termite Reticulitermes lucifugus Rossi in Sicily.

2015

The dynamics of symbiotic protist communities of Reticulitermes lucifugus ‘‘Sicily’’ were investigated to assess the effects of seasonal environmental conditions and the termite’s feeding activity. In worker and soldier castes, the total protist population (total abundance), individual species abundances, and species proportions in their hindguts were examined monthly from December 2012 to February 2014. The main protist species taken into account were Dinenympha fimbriata Kirby, D. gracilis Leidy, Pyrsonympha flagellata Gras., Spirotrichonympha flagellata Grassi u. Fo` a, Holomastigotes elongatum Grassi u. Fo`a, and Trichonympha agilis Leidy, while others were not specifically identified, …

Social immunity: why we should study its nature, evolution and functions across all social systems.

2018

Mounting defences against pathogens is a necessity for all animals. Although these defences have long been known to rely on individual processes such as the immune system, recent studies have emphasized the importance of social defences for group-living hosts. These defences, called social immunity, have been mostly studied in eusocial insects such as bees, termites and ants, and include, for instance, mutual cleaning and waste management. Over the last few years, however, a growing number of works called for a broader exploration of social immunity in non-eusocial species. In this review, we summarize the rationales of this call and examine why it may provide major insights into our curren…

Host-ectoparasite associations; the role of host traits, season and habitat on parasitism interactions of the rodents of northeastern Iran

2021

Abstract Background Rodents play a significant role as reservoirs of zoonotic diseases. Nevertheless, their ectoparasite assemblage and host-ectoparasite associations are poorly known. This study intended to give new insights on the relationships between ectoparasites and rodents in northeastern Iran. Methods Rodents were captured using live traps during the year of 2016–2020 and their ectoparasites were collected. Parasitological indices such as infestation rate, prevalence and mean intensity of infestation were analyzed. Results A total of 284 rodents, belonging to 17 species, were trapped which infested by 178 ectoparasites from five orders Siphonaptera, Phthiraptera, Ixodida, Mesostigma…