Endophagy of biting midges attacking cavity-nesting birds

Area of Science:

• Veterinary Entomology
• Medical Entomology
• Ecology of Disease Vectors

Background:

• Host-seeking behavior (exophagy vs. endophagy) in blood-feeding Diptera influences pathogen transmission dynamics.
• Ornithophilic biting midges (Ceratopogonidae) and blackflies (Simuliidae) are typically considered strictly exophagous, feeding outdoors.

Purpose of the Study:

• To investigate the host-seeking behavior of ornithophilic Diptera, specifically examining endophagy in biting midges within bird nest cavities.
• To determine if biting midges and blackflies utilize enclosed avian habitats for blood-feeding.

Main Methods:

• Deployment of sticky foil traps within artificial nest boxes to capture blood-feeding Diptera.
• Identification of captured midge species and confirmation of avian blood meals using DNA analysis.
• Observation of blackfly presence or absence in nest box traps.

Main Results:

• 667 female biting midges from eight Culicoides species were captured, with Culicoides truncorum dominating.
• DNA analysis confirmed avian blood meals in engorged midges.
• Three species—Culicoides truncorum, C. pictipennis, and C. minutissimus—demonstrated endophagy by feeding within nest boxes.
• No blackflies were captured in the nest boxes, supporting their exophagous behavior.

Conclusions:

• This research provides the first evidence of endophagy in ornithophilic biting midges, challenging previous assumptions.
• The findings highlight the importance of considering endophagy in biting midge host preferences for understanding disease transmission.
• The confirmed exophagy of blackflies and the endophagy of certain midge species have implications for vector surveillance and control strategies targeting avian pathogens.