Absence of nectar resource partitioning in a community of parasitoid wasps

Abstract

Parasitoid wasps occur in diverse communities, with the adults of most species sourcing carbohydrates from nectar or honeydew. However, the role of niche partitioning of nectar resources in maintaining diverse communities of parasitoid Hymenoptera is poorly known. To elucidate patterns of nectar resource use and test whether species partition resources, we investigated pollen loads in a community of parasitoid thynnine wasps in the biodiversity hotspot of southwestern Australia. In total, 304 thynnine wasps from 28 species were captured. Eighteen of these species are undescribed, highlighting the high diversity of unrecognized species in southwestern Australia. Pollen loads were detected on 111 individuals representing 19 species. Six pollen types were identified. All species that carried pollen primarily visited two tree species, Agonis flexuosa and Eucalyptus marginata, in the Myrtaceae. The other four pollen types were only recorded from single wasps. There was no evidence of nectar-resource partitioning. This may be due to these Myrtaceae producing abundant, open-faced flowers. Wasp species that were not recorded carrying pollen may utilise other carbohydrate sources, such as homopoteran honeydew. Niche partitioning is predicted to occur during the parasitoid larval phase of the life cycle. This study highlights the importance of nectariferous Myrtaceae in supporting diverse wasp communities. Further, two species of nectarforaging wasps collected here are involved in the pollination of rare orchid species. Hence, conservation and management of habitats that support floriferous Myrtaceae are important for both the maintenance of diverse wasp communities, and the plants they pollinate.

Evolutionary relationships among pollinators and repeated pollinator sharing in sexually deceptive orchids

“…Examination of the flight times of the most diverse genera (and most others known) confirms that they contain spring‐flying species that fly during the peak flowering time of sexually deceptive orchids in south‐western Australia (G.R. Brown, unpublished data; Menz et al ., ). Further, they almost all fall within the considerable range of body sizes evident in the known pollinators of sexually deceptive orchids (R.D.…”

“…Given that sexually deceptive orchids occur in almost all terrestrial habitats within south‐western Australia (Hoffman & Brown, ), it also seems unlikely that differences in habitat preference would prevent wasp genera from being exploited. However, a recent community study showing that genera involved in orchid pollination tend to be nectarivores (Menz et al ., ) raises the intriguing possibility that nectar‐feeding thynnines may facilitate the evolution of sexual deception through a greater ability to detect floral signals or a bias towards responding to them.…”

Pollinator rarity as a threat to a plant with a specialized pollination system

“…Baiting at over 90 sites across the geographical range of C. huegelii yielded a single taxon of sexually deceived pollinator, the small form of M. insignis , despite the presence of diverse thynnine wasp communities in these habitats (Menz et al ., ). This apparently high specificity matches other sexually deceptive orchids, which are typically pollinated by one or few insect species (Phillips et al ., ; Gaskett, ).…”

Record of Animals Association with Xanthostemon novoguineensis (Valeton)

“…Then, the pollination process occurs and it aids the sustainable of the plant itself. Menz et al (2015) report that wasps often visited Agonis flexusa and Eucalyptus marginata (Myrtaceae). Interestingly, it has been proven that many pollens attached to the body of wasps.…”