Orthoptera, a new order of pollinator

Area of Science:

• Evolutionary Ecology
• Orchidaceae Pollination Biology
• Tropical Biodiversity

Background:

• Orchidaceae exhibit diverse pollinator-linked floral forms, with Angraecum orchids traditionally associated with hawkmoth pollination.
• Pollinator identity and specificity in orchids, particularly in tropical diversification hotspots, remain understudied.
• Angraecum, a genus of tropical Old World orchids, has been a model for studying hawkmoth pollination due to specialized floral morphology.

Purpose of the Study:

• To investigate the pollination biology of Angraecum cadetii, an endemic orchid species from Mauritius and Reunion.
• To identify natural pollinators and assess their efficiency and impact on reproductive success.
• To characterize floral traits, including spur length, nectar, and scent, in relation to pollination.

Main Methods:

• Field observations using camcorders to record natural pollinator interactions with A. cadetii flowers.
• Quantification of pollinator efficiency through pollen removal and deposition measurements.
• Assessment of reproductive success via fruit set measurements over three flowering seasons.
• Analysis of floral traits such as spur length, nectar volume/concentration, and scent production.

Main Results:

• Angraecum cadetii is self-compatible but requires pollination for fruit set.
• An undescribed species of raspy cricket (Orthoptera) was identified as the sole pollinator.
• Crickets, nocturnal foragers, exhibited prolonged flower visits (avg. 16.5s) and probed fresh flowers.
• Pollen removal occurred in 46.5% of flowers, with pollinia deposition in 27.5%, leading to fruit set ranging from 11.9% to 43.4%.

Conclusions:

• This study provides the first well-supported evidence of orthopteran-mediated pollination in flowering plants.
• The findings challenge the exclusive association of Angraecum orchids with hawkmoth pollination.
• The discovery underscores the importance of exploring diverse pollinator groups in understanding plant reproductive strategies.