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ABSTRACT: A challenge for parasites is how to evade the sophisticated detection and rejection abilities of potential hosts. Many studies
have shown how insect social parasites overcome host recognition systems and successfully enter host colonies. However, once
a social parasite has successfully usurped an alien nest, its brood still face the challenge of avoiding host recognition.
How immature stages of parasites fool the hosts has been little studied in social insects, though this has been deeply investigated
in birds. We look at how larvae of the paper wasp obligate social parasite Polistes sulcifer fool their hosts. We focus on cuticular hydrocarbons (CHCs), which are keys for adult recognition, and use behavioral recognition
assays. Parasite larvae might camouflage themselves either by underproducing CHCs (odorless hypothesis) or by acquiring a
chemical profile that matches that of their hosts. GC/MS analyses show that parasite larvae do not have lower levels of CHCs
and that their CHCs profile is similar to the host larval profile but shows a reduced colony specificity. Behavioral tests
show that the hosts discriminate against alien conspecific larvae from different colonies but are more tolerant towards parasite
larvae. Our results demonstrate that parasite larvae have evolved a host larval profile, which overcomes the host colony recognition
system probably because of the lower proportion of branched compounds compared to host larvae. In some ways, this is a similar
hypothesis to the odorless hypothesis, but it assumes that the parasite larvae are covered by a chemical blend that is not
meaningful to the host.
Behavioral Ecology and Sociobiology 03/2008; 62(8):1319-1331. · 3.18 Impact Factor
