Oecologia (2016) 182, 111-118
Mikaël Bili, A.M. Cortesero, Y. Outreman and D. Poinsot (2016)
Host specialisation and competition asymmetry in coleopteran parasitoids
Oecologia 182 (1), 111-118
Abstract: When specialists and generalists compete for a limited resource, specialists are more constrained because they are less likely to find an alternative resource. In parasitoids with overlapping host ranges, asymmetric competition should therefore exist where specialists are more likely to win the host in a contest. Competition between parasitoids has been studied mostly in hymenopterans. In hymenopteran parasitoid wasps, females must reach the host to lay their eggs and can thus strongly influence the outcome of competition between future offspring by killing eggs or larvae of competitors. We studied competition between the free-ranging larvae of two sympatric coleopteran parasitoid rove beetles (one specialist, Aleochara bilineata and a generalist, Aleochara bipustulata) with overlapping host ranges competing in agricultural fields for pupae of the cabbage root fly. In these species, females lay their eggs in the soil, then first instars find the host where they will develop as solitary parasitoids and deal with potential competitors. Because adult longevity and fecundity favour the generalist, we postulated that first instars of the specialist would be superior larval competitors. Accordingly, we studied the outcome of encounters between first instars of the two species provided with a single host. Irrespective of its release prior to or simultaneously with its generalist competitor, the larva of the specialist most often won. Moreover, specialist larvae still won half of the encounters when generalist larvae were given a 24-h advantage. This might explain the coexistence of the two species in the field.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Yannick Outreman, Anne Marie Cortesero
Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Delia radicum | ||||
| Aleochara bilineata (parasitoid) | Delia radicum | |||
| Aleochara bipustulata (parasitoid) | Delia radicum |
