Insectes Sociaux最新文献

Intraspecific competition is a fundamental ecological process. Studies in ants have explored this mainly in the context of foraging. There is a notable gap in our understanding of competition dynamics during goal-oriented task of colony relocation even though this task impacts the survival and fitness of colonies. Here, we instigated a competition between equal (n = 17) and unequal (n = 14) sized Diacamma indicum colonies for a new nest and contrasted our findings with two sets of controls—colonies that relocated without facing any competition and colonies that did not relocate. In majority of the trials, one colony successfully occupied the new nest and colony size was a factor in determining this success. In addition, colonies with more explorers and lower latency to start recruitment had a significantly higher chance of occupying the new nest. In 23% of the trials, both colonies merged, following cross colony tandem recruitment and one of the gamergates was killed. The level of aggression displayed by the competing colonies was comparable, but the wining colonies had a lower percentage of colony involved in aggression. Higher levels of aggression were noted in the area close to at the old and new nest site. Further, there was exchange of pupae between competing colonies and larger colonies showed 2.86 times higher pupae theft. Losing colonies experienced significantly higher mortality as compared to controls. Winning colonies experienced higher mortality as compared to non relocating controls. This study showcases how intraspecific competition during colony relocation shapes colony composition, fitness and population dynamics in an ant community.

Despite the extraordinary diversity of organisms associated with ants, few species or genera have been inventoried for the myrmecophilous communities they host. Here, we review the known information on Lepidoptera associated with the ant genus Ectatomma, based on: (a) extensive colony sampling and observations on six focal species (E. tuberculatum, E. brunneum, and four cryptic species of the E. ruidum species complex) over a period of 43 years in Mexico, French Guiana, and Colombia, (b) a follow-up of the available literature, and (c) an analysis of Ectatomma images from various photographic databases available online and direct observations in Brazil and Suriname. No lepidopteran species were found inside the nests, but a wide variety of facultative mutualisms were observed outside on plants bearing extrafloral nectaries and/or honeydew-producing hemipterans; however, around 15% involved a form of commensalism, with no direct physical butterfly–ant interaction. Various new associations, previously unnoticed, are reported, and we illustrate a new symbiotic association between Rekoa palegon and E. ruidum sp. 2 in Mexico. At least 29 lepidopteran species from 19 genera, belonging to four tribes in three subfamilies and three families, participate in 41 associations involving only 5 of the 18 known Ectatomma species, all 5 characterized by visiting liquid food sources on foliage. Specialized interactions with Ectatomma ants were only found in three Riodinidae species, while in Lycaenidae interactions were all facultative. A greater sampling effort is needed, including nocturnal sampling and studies on little-studied species of this genus, to obtain a comprehensive picture of the extent of Ectatomma–Lepidoptera interactions.

In this review, we explore the social behavior of the fruit fly Drosophila melanogaster, integrating mechanistic, ecological and evolutionary perspectives. Despite its status as a major laboratory model organism, D. melanogaster’s social life remains generally underappreciated by biologists. Adult flies attract others to food sources through pheromone deposition, leading to group formation. Within these groups, males engage in competitive reproductive behaviors while females adopt complex mating patterns and lay eggs communally. Both sexes adapt their reproductive behaviors to early as well as current social experience. Communal egg-laying by females promotes larval group formation, with larvae cooperating to dig tunnels for protection and breathing while feeding. Aggregation is also visible at the pupal stage, suggesting a social dimension to the entire life cycle of this species. We examine the competitive and cooperative behaviors of D. melanogaster, considering the ecological context (resource distribution, predation, parasitism pressures, and reproductive strategies) that influences these social interactions. We also discuss how individual behavior and physiology varies with group size and diversity, potentially as an adaptation to the costs and benefits of being in a group. This review underscores the potential of fruit flies in advancing research on social interactions and dynamics, demonstrating their usefulness for the fields of sociality, evolution and social neurosciences.

Many social insects use pheromone trails to recruit workers to resources. Pheromone trails have some limitations, however. Two major limitations are that they evaporate over time, meaning that more distant locations may be more difficult to recruit precisely to, and that they cannot be removed if laid erroneously, or if they become outdated. Here, we ask whether Lasius niger ants can adaptively modulate pheromone deposition to overcome these limitations. Specifically, we first ask whether ants which have followed a pheromone trail to a wrong (unrewarded) location upregulate pheromone deposition to the correct food location to compete with the erroneous trail. They do not. Then, we examine how food distance and proximity to food influence pheromone deposition. We find that ants deposit up to 22 times more pheromone within 10 cm of a food source compared to when they are about to reach the nest. Moreover, they deposit up to four times more pheromone next to a food source placed 100 cm away from the nest as compared to one placed 20 cm away from the nest. Lasius niger ants thus do not display a mechanism for overcoming outdated or erroneously-laid trails by strengthening correct alternatives in our experiment, but do strongly upregulate recruitment to more distant food sources, which are more difficult to locate and recruit to.

The ability to keep stable, healthy colonies in laboratory settings is fundamental for conducting research on ants and particularly important for developing management tools for pest species. An important component for successful ant rearing is a suitable diet and a number of diets for feeding ants have been developed. Calcium caseinate as a protein supplement has been a widely used ingredient in ant diets, but it has become difficult to obtain. Therefore, there is a need to find an alternative protein supplement for rearing ants in captivity. Using the ant Nylanderia fulva as a model, the suitability of four alternative diets was tested against a calcium caseinate containing diet: (1) whey protein isolate fortified with calcium, (2) whey protein isolate, (3) sodium caseinate, and (4) cricket powder. We tested the performance of colony fragments fed on diets by comparing worker and queen mortality, as well as brood production for 6 weeks. Diet containing cricket powder performed better than all other diets, reflected by lower worker mortality and the addition of new workers and brood to the colony fragment, resulting in colony growth. Considering recent developments in the production of cricket powder making it a low cost and readily accessible ingredient, it should prove an effective protein supplement for rearing ants in captivity for other species.

Human activity is one of the major causes of biodiversity loss in both plants and animals, as it can disrupt biological interactions and jeopardise the balance of ecosystems. Despite the implementation of conservation and environmental care policies, their management requires long-term monitoring and incurs high costs. In search of efficient solutions, bioindicator species have been implemented as cost-effective and time-efficient alternatives. Given their diverse roles within terrestrial ecosystems, ants serve as an ideal model group for assessing environmental health and changes in biodiversity. In this study, we focused on identifying disturbance-indicator ant species in various regions of Mexico and analysed their potential geographic distribution patterns. Information was gathered from various sources, including databases, entomological collections, and scientific articles. The human footprint was utilised to categorise ant species based on their impact in Mexico. Using the indicator species value (IndVal) method, 21 ant species indicatives of disturbance were determined across eight Mexican provinces. Eleven of these species exhibited widespread distributions, primarily in vegetation-deprived areas and human settlements. The presence of invasive exotic species, such as Paratrechina longicornis and Wasmannia auropunctata, underscores the need to assess their risks, identify invasion patterns, and develop control and conservation strategies. We provide a list of ecologically relevant ant species in Mexico, establishing a baseline for proposing conservation and effective biodiversity management strategies.

Social aphids have received increasing attention from sociobiologists as they offer novel systems for the study of the origins and maintenance of social behavior. All aphids undergo clonal reproduction in their life cycles, which has consequences for kin structure and social dynamics in aphid colonies. Although most of the known social aphids are defined by the presence of defender morphs, others, such as Tamalia gall aphids, exhibit communal behavior by foundresses when occupying galls, which raises questions about the circumstances favoring such behavior. Co-occupation of galls has opened the door towards exploitation by inquiline Tamalia aphids acting as obligate parasites of gall-inducers. Inquilines compete successfully with their host aphids in reproduction output and, possibly, developmental rates, but the mechanisms behind these advantages are not yet understood.

Fallen twigs on forest floors are an important nesting resource for ants. Despite their abundance in the leaf litter, these twigs are not always colonized, since various attributes affect their occupancy. However, the morphological parameters of ants are potentially linked to the entrance hole size in arboreal species, which will vary among castes. We therefore tested for the relation between the ant morphological traits of different castes and the size of entrance holes in twigs, using communities collected in the leaf litter in areas of the Brazilian Atlantic Forest. We measured a total of 4,159 ant individuals across 60 species and their female castes, and dissected 4,805 twigs, of which 1,064 had entrance holes, 519 hosted ants. The entrance hole size of twigs was also measured. We observed average ant morphological traits (per colony or species level) were positively related to the average size of the entrance holes in the twigs. At the colony level, all five morphological variables measured (head width, head length, scape length, Weber's length, and hind femur length) were related to the entrance hole size in workers and majors, and the same was true for queens except for scape length. At the species level, this pattern was maintained for workers and queens, but in majors hole sizes were only related to their head width. We conclude that the size of the entrance hole is a relevant variable for the occupancy of twigs in the leaf litter by morphologically variable species of twig-nesting ants.

Among eusocial insects, ants show the most advanced morphological division of labor with large winged queens, smaller wingless workers, and phenotypically intermediate castes. These intermediate castes may have evolved from the selection of developmental errors called intercastes. Intercastes are unusual phenotypes that show uncoordinated expression of worker and queen traits. These rare specimens provide remarkable insights into the advanced morphological evolution of the division of labor unique to ants. While they have been reported in several genera of the subfamily Myrmicinae, a single recent study described intercastes in the genus Aphaenogaster (210 spp). Here, we provide the first record of intercastes in an Asian species, Aphaenogaster rugulosa, endemic to the Japanese island of Yonaguni-jima. Using allometric measurements, scanning electron microscopy and dissections, we describe the trait combination of seven intercastes and compare it to worker and queen phenotypes. We discuss the modular origin of these rare phenotypes and elaborate on the potential role of intercastes in ant evolution.

When we think of social insects, earwigs rarely come to mind. This is perhaps not surprising, as the term ‘social insect’ has often been used in the literature to refer exclusively to ‘eusocial insects’, i.e. ants, termites and certain bees and wasps. However, earwigs show many aspects of social life. Social interactions in earwigs can occur in groups of up to several hundred individuals, with mothers providing extensive forms of care for their eggs and juveniles, and adults and juveniles showing cooperative behaviour with group members of the same and different ages. In this review, we discuss how research on the European earwig (by far the most studied dermapteran species in terms of its social life) can improve our general understanding of social evolution in insects. After outlining (1) its life cycle and (2) its multiple forms of sociality, we explain how this species advances our knowledge of (3) the interplay between social conflict and cooperation in maintaining facultative social life, (4) the role of pathogens and symbionts in the transition between solitary and social life, (5) the impact of anthropogenic change on social evolution, and (6) the chemical, hormonal and genetic regulation of facultative social behaviour. Overall, this review highlights that the study of social species such as the European earwig can provide unique insights into our general understanding of social evolution and the early evolutionary transitions from solitary to group living.