Sugar feeding in adult stable flies

Authors: Taylor, David; Berkebile, Dennis

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/8/2008
Publication Date: 6/19/2008
Citation: Taylor, D.B., Berkebile, D.R. 2008. Sugar feeding in adult stable flies. Environmental Entomology. 37(3):625-629.

Interpretive Summary: Stable fly adults are blood feeding pests of humans and livestock. Although blood is required for male and female stable flies to reproduce, both sexes will also feed on sugars in the laboratory if provided. The extent and role of sugar feeding in the biology of stable flies is unclear. In this study, we examined the frequency of sugar feeding in stable fly populations from both rural and urban environments in eastern Nebraska. Twelve percent of field collected stable flies had fed on sugars. More flies from the urban environment had fed on sugars than from the rural environment. Slightly more females had sugar fed than males. Only 0.8% of the flies had visible signs of blood in their guts. Based upon laboratory studies of digestion times for blood and sugar, we were able to calculate that approximately 5% of the flies had sugar fed during the past 24 hours compared with 2.5% of the flies having blood fed. Hence, the frequency of sugar feeding appears to be double that of blood feeding. Sugar feeding is an important component of the biology of adult stable flies which has not been exploited for the development of integrated control strategies.

Technical Abstract: Adult stable flies, (Stomoxys calcitrans (L.)), are known to feed readily on sugars in the laboratory. However, little is known concerning the extent of stable fly sugar feeding in wild populations. We examined the frequency of sugar feeding in stable flies in rural and urban environments. In addition, to determine the relationship between sugar feeding and blood feeding, stable flies were visually examined to determine if blood was present in the gut. In laboratory studies, sugars were detectable with the anthrone technique in stable flies for approximately 3 days after being imbibed and blood could be visually detected in the gut for 24 to 48 hours after feeding. Twelve percent of the field collected flies had detectable sugar with a higher percentage of the urban flies having sugar fed than the rural flies, 21% and 8% respectively. Female flies sugar fed at a slightly higher rate than males, 13 verses 11%, respectively. Less than 1% of the field collected flies had blood in their guts. The frequency of observable blood was slightly higher in flies collected in an urban environment when compared with those collected in a rural environment and did not differ between male and female flies. The number of flies with both blood and sugar was slightly higher than would be expected based upon the frequencies of each alone. Seasonal patterns of both sugar feeding and blood feeding were similar in the rural and urban environments; both peaked in the early summer, May – mid-June, and dropped through the summer and fall. Sugar feeding in the urban environment increased again in October.