Higher aggression towards closer relatives by soldier larvae in a polyembryonic wasp

In the polyembryonic wasp Copidosoma floridanum, females commonly lay one male and one female egg in a lepidopteran host. Both sexes proliferate clonally within the growing host larva. Distinct larval castes develop from each wasp egg, the majority being ‘reproductives’ plus some ‘soldiers’ which sa...

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Main Authors: Dunn, Johanna, Dunn, Derek W., Strand, Michael R., Hardy, Ian C.W.
Format: Article
Published: Royal Society 2014
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Online Access:https://eprints.nottingham.ac.uk/41478/
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author Dunn, Johanna
Dunn, Derek W.
Strand, Michael R.
Hardy, Ian C.W.
author_facet Dunn, Johanna
Dunn, Derek W.
Strand, Michael R.
Hardy, Ian C.W.
author_sort Dunn, Johanna
building Nottingham Research Data Repository
collection Online Access
description In the polyembryonic wasp Copidosoma floridanum, females commonly lay one male and one female egg in a lepidopteran host. Both sexes proliferate clonally within the growing host larva. Distinct larval castes develop from each wasp egg, the majority being ‘reproductives’ plus some ‘soldiers’ which sacrifice reproduction and attack competitors. Maturing mixed sex broods are usually female biased, as expected when intra-brood mating is common. Pre-mating dispersal followed by outbreeding is expected to increase sexual conflict over brood sex ratios and result in greater soldier attack rates. Owing to sexually asymmetric relatedness, intra-brood conflicts are expected to be resolved primarily via female soldier attack. We observed soldier behaviour in vitro to test whether lower intra-brood relatedness (siblings from either within-strain or between-strain crosses were presented) increased inter-sexual aggression by female as well as male soldiers. As found in prior studies, females were more aggressive than males but, contrary to expectations and previous empirical observations, soldiers of both sexes showed more aggression towards more closely related embryos. We speculate that lower intra-brood relatedness indicates maternal outbreeding and may suggest a rarity of mating opportunities for reproductives maturing from the current brood, which may enhance the value of opposite sex brood-mates, or that higher aggression towards relatives may be a side-effect of mechanisms to discriminate heterospecific competitors.
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spelling nottingham-414782020-05-04T16:47:32Z https://eprints.nottingham.ac.uk/41478/ Higher aggression towards closer relatives by soldier larvae in a polyembryonic wasp Dunn, Johanna Dunn, Derek W. Strand, Michael R. Hardy, Ian C.W. In the polyembryonic wasp Copidosoma floridanum, females commonly lay one male and one female egg in a lepidopteran host. Both sexes proliferate clonally within the growing host larva. Distinct larval castes develop from each wasp egg, the majority being ‘reproductives’ plus some ‘soldiers’ which sacrifice reproduction and attack competitors. Maturing mixed sex broods are usually female biased, as expected when intra-brood mating is common. Pre-mating dispersal followed by outbreeding is expected to increase sexual conflict over brood sex ratios and result in greater soldier attack rates. Owing to sexually asymmetric relatedness, intra-brood conflicts are expected to be resolved primarily via female soldier attack. We observed soldier behaviour in vitro to test whether lower intra-brood relatedness (siblings from either within-strain or between-strain crosses were presented) increased inter-sexual aggression by female as well as male soldiers. As found in prior studies, females were more aggressive than males but, contrary to expectations and previous empirical observations, soldiers of both sexes showed more aggression towards more closely related embryos. We speculate that lower intra-brood relatedness indicates maternal outbreeding and may suggest a rarity of mating opportunities for reproductives maturing from the current brood, which may enhance the value of opposite sex brood-mates, or that higher aggression towards relatives may be a side-effect of mechanisms to discriminate heterospecific competitors. Royal Society 2014-05-28 Article PeerReviewed Dunn, Johanna, Dunn, Derek W., Strand, Michael R. and Hardy, Ian C.W. (2014) Higher aggression towards closer relatives by soldier larvae in a polyembryonic wasp. Biology Letters, 10 (5). 20140229/1-20140229/4. ISSN 1744-957X aggression relatedness polyembryonic wasps http://rsbl.royalsocietypublishing.org/content/10/5/20140229.article-info doi:10.1098/rsbl.2014.0229 doi:10.1098/rsbl.2014.0229
spellingShingle aggression
relatedness
polyembryonic wasps
Dunn, Johanna
Dunn, Derek W.
Strand, Michael R.
Hardy, Ian C.W.
Higher aggression towards closer relatives by soldier larvae in a polyembryonic wasp
title Higher aggression towards closer relatives by soldier larvae in a polyembryonic wasp
title_full Higher aggression towards closer relatives by soldier larvae in a polyembryonic wasp
title_fullStr Higher aggression towards closer relatives by soldier larvae in a polyembryonic wasp
title_full_unstemmed Higher aggression towards closer relatives by soldier larvae in a polyembryonic wasp
title_short Higher aggression towards closer relatives by soldier larvae in a polyembryonic wasp
title_sort higher aggression towards closer relatives by soldier larvae in a polyembryonic wasp
topic aggression
relatedness
polyembryonic wasps
url https://eprints.nottingham.ac.uk/41478/
https://eprints.nottingham.ac.uk/41478/
https://eprints.nottingham.ac.uk/41478/