Workers of a drywood termite do not work

BACKGROUND: Social insects (ants, bees, wasps and termites) are considered as prime examples of altruism in which individuals (workers) forego their own reproduction to help other individuals reproduce. Such a behaviour is favoured by natural selection because the workers rear close kin and in doing so enhance their inclusive fitness. RESULTS: Here I show, however, that this does not generally apply to termite workers which are scarcely investigated. In the basal drywood termite Cryptotermes secundus the 'workers', which form the large majority of a colony, did not stay to raise relatives. There is no brood caring behaviour and they do not engage in costly help. They are large immature offspring that develop into either winged (dispersing) or unwinged (replacement) reproductives and the probability that they did so was unaffected by the number of brood in the nest as a brood addition experiment showed. CONCLUSION: Thus, in contrast to general perception where termite workers are considered equivalent to workers in Hymenoptera, the 'large immatures' of C. secundus did not behave as workers that help in raising younger siblings. This apparently is not necessary as the colony lives inside its food. These results, which are likely to be typical for wood-dwelling termites, open the possibility that large complex group living can evolve without altruistic helping and that costly altruistic helping by workers in termites evolved only as a second step

Evolution of delayed dispersal and subsequent emergence of helping, with implications for cooperative breeding.

Cooperative breeding occurs when individuals help raise the offspring of others. It is widely accepted that help displayed by cooperative breeders emerged only after individuals\u27 tendency to delay dispersal had become established. We use this idea as a basis for two inclusive-fitness models: one for the evolution of delayed dispersal, and a second for the subsequent emergence of helpful behavior exhibited by non-breeding individuals. We focus on a territorial species in a saturated environment, and allow territories to be inherited by non-breeding individuals who have delayed dispersal. Our first model predicts that increased survivorship and increased fecundity both provide an incentive to non-breeding individuals to delay dispersal, and stay near their natal territory for some period of time. Predictions from the first model can be well understood by ignoring complications arising from competition among relatives. Our second model shows that effects on relatives play a primary role in the advantage of helping. In addition, the second model predicts that increased survivorship and fecundity promote the emergence of help. Together, our models lead us to conclude that the emergence of cooperative-breeding systems is made easier by life-history features associated with high survivorship and fecundity. We discuss the implications of our conclusions for life-history-based hypotheses of cooperative breeding and social evolution

Testing inclusive fitness theory in a lower termite

É o texto da comunicação «Instituto de Arqueologia de Coimbra – ensino, investigação e valorização em Arqueologia», apresentada aos Encontros 100 Anos de Arqueologia – «O Arqueólogo Português» (Vila do Conde, 14-16.06.1996).Apresenta-se, em síntese, o que tem sido e o que se espera continuar a ser a actividade dos membros do Instituto de Arqueologia da Universidade de Coimbra, nos campos do ensino, da investigação e da valorização em Arqueologia

Phylogenetic Community Structure of Southern African Termites (Isoptera)

The processes that structure communities are still largely unknown. Therefore, we tested whether southern African termite communities show signs of environmental filtering and/or competition along a rainfall gradient in Namibia using phylogenetic information. Our results revealed a regional species pool of 11 species and we found no evidence for phylogenetic overdispersion or clustering at the local scale. Rather, our results suggest that the assembly of the studied termite communities has as strong random component on the local scale, but that species composition changes along the climatic gradient

Molecular basis for the reproductive division of labour in a lower termite

<p>Abstract</p> <p>Background</p> <p>Polyphenism, the expression of different phenotypes with the same genetic background, is well known for social insects. The substantial physiological and morphological differences among the castes generally are the result of differential gene expression. In lower termites, workers are developmentally flexible to become neotenic replacement reproductives via a single moult after the death of the founding reproductives. Thus, both castes (neotenics and workers) are expected to differ mainly in the expression of genes linked to reproductive division of labour, which constitutes the fundamental basis of insect societies.</p> <p>Results</p> <p>Representational difference analysis of cDNAs was used to study differential gene expression between neotenics and workers in the drywood termite <it>Cryptotermes secundus </it>(Kalotermitidae). We identified and, at least partially cloned five novel genes that were highly expressed in female neotenics. Quantitative real-time PCR analysis of all five genes in different castes (neotenics, founding reproductives, winged sexuals and workers of both sexes) confirmed the differential expression patterns. In addition, the relative expression of these genes was determined in three body parts of female neotenics (head, thorax, and abdomen) using quantitative real-time PCR.</p> <p>Conclusion</p> <p>The identified genes could be involved in the control and regulation of reproductive division of labour. Interestingly, this study revealed an expression pattern partly similar to social Hymenoptera indicating both common and species-specific regulatory mechanisms in hemimetabolous and holometabolous social insects.</p

Heterozygosität und Fitness bei einem bedrohten Singvogel : Blutparasitenbefall wird durch Einzel-Lokus, aber nicht durch Genom-weite Effekte erklärt

In non-pedigreed populations, insights into effects of inbreeding can be obtained by correlations between individual heterozygosity and fitness-related traits (HFCs). Using an information-theoretic approach, we explored whether heterozygosity of microsatellite markers, measured as internal relatedness (IR), is associated with infection by blood parasites (Plasmodium, Trypanosoma, or Leucocytozoon) in the threatened Aquatic Warbler (Acrocephalus paludicola). We also explored whether any of the markers is more influential than others, or than IR, in explaining blood parasitism (single-locus effects). While we observed that IR was a relatively important predictor of Plasmodium parasitism, we did not find strong evidence for IR to correlate with infection by the identified blood parasites, accounting for sex and population effects. Therefore, our data did not support negative inbreeding effects on blood parasite infection in the Aquatic Warbler. However, we found single-locus effects, such that individuals heterozygous at AW-03 and Ase19 had lower probability of infection by blood parasites pooled together and by Plasmodium, respectively. This indicates that these two markers are in linkage disequilibrium with unknown fitness loci which are related to resisting or clearing blood parasites, and which confer a heterozygote advantage in the Aquatic Warbler. Our results add to the growing evidence that single-locus effects contribute more to HFCs than formerly recognized and have implications for Aquatic Warbler conservation

How termite community assembly changes with anthropogenic disturbance in a tropical forest (Togo, West Africa)

Method development is one of the raisons d’etre of engineering design research and method uptake by industry is perceived as an important success criterion. This paper argues that one of the problems with methods is the lack of clarity about what is actually proposed to industry and the academic community when a new method is put forward, in terms of how detailed, strict, precise and rigorous the method is and what it can deliver. This paper puts the concept of method in the context of related concepts and proposes a multi-level model of the elements of a method to argue that a contribution on each of these levels can be of value and that the introduction of methods can fail on each of these levels. Implications thereof for industry and academia are discussed, concluding that a clear description of methods and their intended use is important for enabling proper validation of each of the method’s elements and for communicating methods to academia and industry