The Basic Principles of Kin Sociality and Eusociality: Human Evolution

The paper posits that kin sociality and eusociality are derived from the handicap-care principles based on the need-based care to the handicappers from the caregivers for the self-interest of the caregivers. In this paper, handicap is defined as the difficulty to survive and reproduce independently. Kin sociality is derived from the childhood handicap-care principle where the children are the handicapped children who receive the care from the kin caregivers in the inclusive kin group to survive. The caregiver gives care for its self-interest to reproduce its gene. The individual’s gene of kin sociality contains the handicapped childhood and the caregiving adulthood. Eusociality is derived from the adulthood handicap-care principle where responsible adults are the handicapped adults who give care and receive care at the same time in the interdependent eusocial group to survive and reproduce its gene. Queen bees reproduce, but must receive care from worker bees that work but must rely on queen bees to reproduce. A caregiver gives care for its self-interest to survive and reproduce its gene. The individual’s gene of eusociality contains the handicapped childhood-adulthood and the caregiving adulthood. The chronological sequence of the sociality evolution is individual sociality without handicap, kin sociality with handicapped childhood, and eusociality with handicapped adulthood. Eusociality in humans is derived from bipedalism and the mixed habitat. The chronological sequence of the eusocial human evolution is 1) the eusocial early hominins with bipedalism and the mixed habitat, 2) the eusocial early Homo species with bipedalism, the larger brain, and the open habitat, 3) the eusocial late Homo species with bipedalism, the largest brain, and the unstable habitat, and 4) extended eusocial Homo sapiens with bipedalism, the shrinking brain, omnipresent imagination, and the harsh habitat. The omnipresence of imagination in human culture converts eusociality into extended eusociality with both perception and omnipresent imagination.

Cockroach as the Earliest Eusocial Animal

A completely preserved cockroach Socialaperlucida gen. et sp. nov. （Blattida： Socialidae faro. nov.） is described from the Mesozoic （Albian Early Cretaceous） amber of Archingeay in France. It is categorized within the new family Socialidae, originating from the Mesozoic cockroach family Liberiblattinidae, and representing the sister group to the most basal known eutermite families. Numerous direct and indirect morphological evidence （such as a unique narrow body and pronotum with reduced coloration, legs without carination and with numerous sensillar pitts （forelegs） as adaptations to life in nests analogical to the living termitophillous species; enlarged head, long palps for communication, a general venation modified in a direction towards termites （subcosta and radial vein [R] approximated, R branches approximated, simplified, cross-veins reduced）, and possibly also the development of the breaking forewing sutura for detaching wings after marriage flight）, suggest its eusocial mode of life. Thus, the first eusociality originated within cockroaches, prior to giving birth to termites; termites and Cryptocercus are not directly related. The group of eusocial cockroaches makes termite morphotaxon polyphyletic, but also in this case, the erection of a new order for mastotermites （including Cratomastotermitidae） and/or the inclusion of eusocial, morphological cockroaches within termites appears counterproductive, thus an example of such a general exception to the taxonomical procedure is provided.

Cuticular hydrocarbon profiles differ between ant body parts:implications for communication and our understanding of CHC diffusion

Insect cuticular hydrocarbons(CHCs)serve as communication signals and protect against desiccation.They form complex blends of up to 150 different compounds.Due to differences in molecular packing,CHC classes differ in melting point.Communication is especially important in social insects like ants,which use CHCs to communicate within the colony and to recognize nestmates.Nestmate recognition models often assume a homogenous colony odor,where CHCs are collected,mixed,and redistributed in the postpharyngeal gland(PPG).Via diffusion,recognition cues should evenly spread over the body surface.Hence,CHC composition should be similar across body parts and in the PPG.To test this,we compared CHC composition among whole-body extracts,PPG,legs,thorax,and gaster,across 17 ant species from 3 genera.Quantitative CHC composition differed between body parts,with consistent patterns across species and CHC classes.Early-melting CHC classes were most abundant in the PPG.In contrast,whole body,gaster,thorax,and legs had increasing proportions of CHC classes with higher melting points.Intraindividual CHC variation was highest for rather solid,late-melting CHC classes,suggesting that CHCs differ in their diffusion rates across the body surface.Our results show that body parts strongly differ in CHC composition,either being rich in rather solid,late-melting,or rather liquid,early-melting CHCs.This implies that recognition cues are not homogenously present across the insect body.However,the unequal diffusion of different CHCs represents a biophysical mechanism that enables caste differences despite continuous CHC exchange among colony members.

Biochemical, molecular, and morphological variations of flight muscles before and after dispersal flight in a eusocial termite, Reticulitermes chinensis

Swarming behavior facilitates pair formation,and therefore mating,in many eusocial termites.However,the physiological adjustments and morphological transformations of the flight muscles involved in flying and flightless insect forms are still unclear.Here,we found that the dispersal flight of the eusocial termite Reticulitermes chinensis Snyder led to a gradual decrease in adenosine triphosphate supply from oxidative phospho・rylation,as well as a reduction in the activities of critical mitochondrial respiratory enzymes from preflight to dealation.Correspondingly,using three-dimensional reconstruction and transmission electron microscopy(TEM),the flight muscles were found to be gradually deteriorated during this process.In particular,two tergo-pleural muscles(IItpm5 and IIItpm5)necessary to adjust the rotation of wings for wing shedding behavior were present only in flying alates.These findings suggest that flight muscle systems vary in function and morphology to facilitate the swarming flight procedure,which sheds light on the important role of swarming in successful extension and fecundity of eusocial termites.

Red imported fire ants(Hymenoptera:Formicidae)cover inaccessible surfaces with particles to facilitate food search and transportation

Eusocial insects have evolved diverse particle-use behaviors.A previous study reported that red imported fire ants,Solenopsis invicta Buren,deposited soil particles on substances treated with essential balm,a fire ant repellent.We hypothesized that S.invicta modifies inaccessible surfaces by covering them with soil particles to facilitate food search and transportation.Here,laboratory experiments were conducted to study the particle-covering behavior of.S.invicta in response to viscose surfaces or surfaces treated with essential balm or liquid paraffin in the presence of real food(sausage)or non-food objects(acrylic plates).S.invicta workers deposited significantly more soil particles on these three types of treated surfaces than on untreated surfaces.In addition,significantly more particles were relocated on viscose and parafTin-smeared surfaces in the presence of food than in the presence of non-food objects.The particle-covering behavior on viscose surfaces was also observed in the field.Interestingly,when no soil particles were available,ants searched and transported food on viscose surfaces only if the surfaces were artificially covered with sufficient quantities of soil particles but could not do so on viscose surfaces without soil particles or with insutTicient quantities of soil particles.In addition,ants actively relocated particles to cover viscose surfaces if the transportation distance was within 200 mm,whereas significantly fewer particles were relocated at longer transportation distances(400 mm).Our study provides a novel example of particle use by fire ants during foraging.