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An alternative pathway to eusociality: Exploring the molecular and functional basis of fortress defense
Author(s) -
Lawson Sarah P.,
Sigle Leah T.,
Lind Abigail L.,
Legan Andrew W.,
Mezzanotte Jessica N.,
Honegger HansWilli,
Abbot Patrick
Publication year - 2017
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/evo.13285
Subject(s) - biology , eusociality , aphid , evolutionary biology , insect , social evolution , zoology , polyphenism , ecology , hymenoptera , botany , phenotypic plasticity
Some animals express a form of eusociality known as “fortress defense,” in which defense rather than brood care is the primary social act. Aphids are small plant‐feeding insects, but like termites, some species express division of labor and castes of aggressive juvenile “soldiers.” What is the functional basis of fortress defense eusociality in aphids? Previous work showed that the acquisition of venoms might be a key innovation in aphid social evolution. We show that the lethality of aphid soldiers derives in part from the induction of exaggerated immune responses in insects they attack. Comparisons between closely related social and nonsocial species identified a number of secreted effector molecules that are candidates for immune modulation, including a convergently recruited protease described in unrelated aphid species with venom‐like functions. These results suggest that aphids are capable of antagonizing conserved features of the insect immune response, and provide new insights into the mechanisms underlying the evolution of fortress defense eusociality in aphids.