Haplometrosis and pleometrosis in the antAcromyrmex striatus (Hymenoptera: Formicidae)

Summary Laboratory tests with mated females of the leaf-cutting antsAcromyrmex striatus (Myrmicinae, Attini) were conducted to determine if the colony foundation is a solitary or a mutualistic process. We have also tested the effect of foundresses density and number of available areas in this process. Three bioassays were performed: with single foundresses; with paired foundresses; and with groups of 8 to 18 foundresses. The results suggest that the foundation can be by haplometrosis or pleometrosis, possibly depending on physical distances between or densities of foundresses. Foraging activity was common in haplometrotic queens and in foundress pairs, but no foraging occurred in groups of foundresses.     

黑盾胡蜂单母建群习性的观察

通过引蜂筑巢研究黑盾胡蜂VespabicolorFabricius单母建群的生物学习性。结果表明 :母蜂在最初 3只子代工蜂羽化之前兼负蜂王和工蜂的职能 ,建成外包巢壁内具有 3 4个巢房的小巢 ,饲育的幼虫数不超过 1 7只 ,各虫态历期分别为卵期 5 5d ,幼虫期 1 2d,蛹期 1 2 5d ;母蜂日外勤飞翔次数与天气相关 ,晴天可达 42次 ,其中近 80 %为捕食。作者认为 ,黑盾胡蜂单母建群时期可能是其生活史中既脆弱又关键的阶段。     

Ecological traits and evolutionary sequence of nest establishment in fungus-growing ants (Hymenoptera, Formicidae, Attini)

Neotropical ants in the tribe Attini share the obligatory behaviour of cultivating fungi as an essential food source. Of this complex and well-studied mutualism, little is known about the biological traits of the phylogenetically basal attines, which may offer important clues to the origins and early evolution of this intricate symbiosis. In this paper we focus on the founding of new nests, a key to understanding evolutionary changes in many social insects, which has received comparatively little attention in attine ants. We present a comparative survey of nest-founding behaviour in Attini, based on 441 foundress nests of 20 species in eight attine genera. In general, attine queens are semiclaustral and haplometrotic when founding nests. We show that attine foundresses of most species use an inert platform (discarded forewings, roots, or rocks) on which the incipient fungal garden is physically isolated during nest foundation, and they conduct semiclaustral foundation. This behaviour is not shared with Atta , which places the incipient garden directly on the soil floor of the initial nest chamber, and conducts claustral foundation. Nest-founding maps congruently onto the major clades in attine phylogeny, suggesting that the behavioural mechanisms used to isolate the incipient garden may have been key innovations in the early evolution of attine fungiculture. The evolutionary sequence of gardening in Attini suggests a transformation series from retention and use of detached wings (suspended from the chamber ceiling or placed over the chamber floor) to root-suspension, and finally use of bare soil. We also discuss transitions from semiclaustral to claustral founding, as well as from haplometrosis to pleometrosis, from ecological and evolutionary perspectives.  © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 81 , 39–48.     

闽东约马蜂的生物学习性观察

约马蜂PolistesjokanamaeRadoszkowski是一种习见的社会性天敌昆虫。研究表明约马蜂在闽东地区于4月中旬觅址筑巢,历经40d建成31~40个巢房的小巢。约马蜂1年发生2代,第1代蜂于5月下旬开始羽化,7月初蜂巢拥有职蜂可达30只,每只职蜂日均外勤达14次,群体进入快速增长期;第2代蜂8~9月间出现,雄蜂所占比例超过1/3,群体进入鼎盛期。第2代雌蜂与雄蜂交尾后于11月陆续离巢越冬。幼体发育历期28~37d,与外界气温密切相关,随温度升高而缩短。文中还提出计算幼体发育历期的方法。     

Pleometrosis in phyllode-glueing thrips (Thysanoptera: Phlaeothripidae) on Australian Acacia

Pleometrosis, or colony founding by more than one female, is common in various social insects and it engenders opportunities for social cooperation as well as cheating. The life cycles of four species of thrips on Australian Acacia trees were examined to elucidate the extent and nature of colony founding by multiple individuals. Data from colonies of three species of thrips from the genus Dunatothrips Moulton and one species of Lichanothrips Mound were used to infer the prevalence of pleometrosis in each species. The results indicate that Dunatothrips species show high levels of cofounding, with up to 50% of colonies having more than one foundress. By contrast, colonies of Lichanothrips are predominantly established by a female and a male. As in some communal insects, pleometrosis is facultative in Dunatothrips , foundresses show more or less constant per capita reproduction with foundress number, and the selective pressures for pleometrosis may involve predation pressure during founding or survivorship insurance for the brood. In Lichanothrips , male founders are probably engaging in mate guarding, which also occurs in some species of gall-inducing thrips on Acacia . The differences in founding patterns between Dunatothrips and Lichanothrips may be due in part the nature of their domiciles: Dunatothrips engage in extensive construction of a domicile using anal secretions, whereas many Lichanothrips primarily improve a pre-existing partial enclosure. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 75 , 467–474.