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Foraging Behaviour and Individuality in the Common Wasp (Vespula vulgaris)

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posted on 15.11.2021, 16:03 by Santoro, Davide

The extreme ecological success of insect societies is frequently attributed to the division of labour within their colonies (Chittka & Muller, 2009; Holldobler & Wilson, 2009; E. Wilson & Hölldobler, 2005). Yet, we are far from understanding the causes and consequences of division of labour, implying workers’ specialization (Chittka & Muller, 2009; Dornhaus, 2008). Moreover, little studied is the behaviour of individual workers (Jeanson & Weidenmüller, 2013). Social wasps (Hymenoptera: Vespidae) have received less attention than social bees and ants, and our knowledge of basic aspect of their ecology is still poor (Jeanne, 1991; Greene, 1991). With my thesis, I aimed to contribute to a better understanding of the common wasp (Vespula vulgaris) foraging ecology and organization of labour. With a particular attention to their foraging behaviour, I investigated the inter-individual variability among wasp workers and their cooperation.  My thesis shows evidence of information sharing and co-ordination in V. vulgaris foragers’ activity. In fact, the discovery and choice of resources by wasp foragers was assisted by information provided by experienced nestmates (Chapter 2). When resources known to portion of the workforce became newly available, the foraging effort of the whole colony increased. My observations of common wasps are hence consistent with foraging activation mechanisms and suggest piloting (in which one individual leads one or more nestmates to a resource) as a possible foraging recruitment mechanism in social wasps.  I found huge variation in lifetime activity, task performance, and survival among common wasp workers (Chapter 3). Some individuals specialized on alternative foraging tasks over their lifetime, and a minority individuals performed a disproportionately high number of foraging trips (elitism). Foragers appeared to become more successful with age, accomplishing more trips and carrying heavier fluid loads. Compared to smaller nestmates, larger wasps contributed more to the colony foraging economies. High mortality was associated with the beginning of the foraging activity, relative to lower mortality in more experienced workers.  I evaluated the performance of common wasp workers within the same insect colony, and found empirical support for the hypothesis that specialist foragers are more efficient than generalists (Chapter 4). In fact, V. vulgaris behavioural specialists performed more trips per foraging day and their trips tended to be shorter. Despite their more intense foraging effort, specialists lived longer than generalists.  I investigated the intra-colonial variation in the sting extension response (SER) of common wasps, measured as a proxy for individual aggressiveness (Chapter 5). I found that wasps vary greatly in their SER and that individuals change during their life. Aggressive individuals tended to become more docile, while docile individuals more aggressive. Older wasps tended to be more aggressive. Wasp size was not significantly related to the SER. Wasp foragers had a less pronounced sting extension than individuals previously involved in nest defence. For the same individual, the aggressive response was proportional to the intensity of the negative stimulus.

History

Copyright Date

01/01/2015

Date of Award

01/01/2015

Publisher

Te Herenga Waka—Victoria University of Wellington

Rights License

Author Retains Copyright

Degree Discipline

Ecology and Evolutionary Biology

Degree Grantor

Te Herenga Waka—Victoria University of Wellington

Degree Level

Doctoral

Degree Name

Doctor of Philosophy

ANZSRC Type Of Activity code

1 Pure Basic Research

Victoria University of Wellington Item Type

Awarded Doctoral Thesis

Language

en_NZ

Victoria University of Wellington School

School of Biological Sciences

Advisors

Lester, Phil; Hartley, Stephen