@article {Couvillon:May 2008:0340-5443:1099,
	author = "Couvillon, Margaret",
	author = "Ratnieks, Francis",
	title = "Odour transfer in stingless bee marmelada (Frieseomelitta varia) demonstrates that entrance guards use an undesirableabsent recognition system",
	journal = "Behavioral Ecology and Sociobiology",
	volume = "62",
	year = "May 2008",
	abstract = "In group-level recognition, discriminators use sensory information to distinguish group members and non-members. For example, entrance guards in eusocial insect colonies discriminate nestmates from intruders by comparing their odour with a template of the colony odour. Despite being a species-rich group of eusocial bees closely related to the honey bees, stingless bee nestmate recognition is a relatively little-studied area. We studied <I>Frieseomelitta varia</I>, a common Brazilian species of stingless bee known as marmelada. By measuring the rejection rates of nestmate and non-nestmate worker bees by guards, we were able to show that guards became significantly less accepting (from 91 to 46%) of nestmates that had acquired odour cues from non-nestmate workers; however, guards did not become significantly more accepting (from 31 to 42%) of non-nestmates that had acquired equivalent amounts of odour cues from the guard's nestmates. These data strongly suggest that guards use an &#8220;undesirable-absent&#8221; system in recognition, whereby incoming conspecific workers are only accepted if undesirable cues are absent, despite the presence of desirable cues. We suggest that an undesirable-absent system is adaptive because robbing by conspecifics may be an important selective factor in <I>F. varia</I>, which would lead to selection for a non-permissive acceptance strategy by guards.",
	pages = "1099-1105(7)",
	url = "http://www.ingentaconnect.com/content/klu/265/2008/00000062/00000007/00000537"
	doi = "doi:10.1007/s00265-007-0537-5"
}