Behaviour, morphology and the division of labour in two soldier-producing aphids

Shingleton, AW Foster, WA

Aw. Shingleton et Wa. Foster, Behaviour, morphology and the division of labour in two soldier-producing aphids, ANIM BEHAV, 62, 2001, pp. 671-679

37

INGLESE

Article

Animal Sciences","Neurosciences & Behavoir

ANIMAL BEHAVIOUR

0003-3472 → ACNP

62

2001

4

671 - 679

ISI

0003-3472(200110)62:<671:BMATDO>2.0.ZU;2-L

In social insects the division of tabour will reflect the trade-off between behavioural flexibility and physical specialization of workers. We investi gated this trade-off in two social aphids: Pseudoregma sundanica (Van der G oot) and P. nicolaiae (Takahashi) (Hormaphididae: Cerataphidini). They are sibling species that produce dimorphic first-instar larvae of soldiers and nonsoldiers. Defence is ostensibly the task of soldiers, but P. sundanica i s also defended by tending ants. We determined the extent to which physical castes are developed in both species by measuring the lengths of various b ody parts of soldier and nonsoldier first instars. We also measured the def ensive behaviour of soldiers and nonsoldiers by confronting them with aggre ssive stimuli. The soldiers and nonsoldiers of P. nicolaiae were morphologi cally and behaviourally more similar than those of P. sundanica, and the no nsoldiers showed greater behavioural plasticity. This suggests a more flexi ble division of tabour in P. nicolaiae, with nonsoldiers being recruited to defensive tasks. Across both castes first-instar larvae were also more agg ressive in P. nicolaiae than in P. sundanica. We relate these findings to t he differences in ant tending in the two species. The data suggest that the caste structure of the social aphids is more complex than expected, and is perhaps more similar to that of the social Hymenoptera. (C) 2001 The Assoc iation for the Study of Animal Behaviour.