Location: Mosquito and Fly Research Unit
Title: Spatial distribution, seasonality and trap preference of stable fly, Stomoxys calcitrans L. (Diptera: Muscidae), adults on a 12-hectare zoological park Authors
|Ose, Gregory -|
Submitted to: Journal of Zoo Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 14, 2014
Publication Date: June 2, 2014
Citation: Ose, G.A., Hogsette, Jr, J.A. 2014. Spatial distribution, seasonality and trap preference of stable fly, Stomoxys calcitrans L. (Diptera: Muscidae), adults on a 12-hectare zoological park. Journal of Zoo Biology. 33:228-233. Interpretive Summary: Stomoxys calcitrans (L.) is a biting fly of extreme economic importance (Bishopp 1913, Taylor et al. 2012) and can cause adverse economic effects on host animals (Campbell et al. 2001). Both males and females feed on blood, often, but not always, derived from ungulates (e.g., livestock-including cattle, goats, sheep, and equines) (Hafez and Gamal-Eddin 1959). Although adults feed on nectar for maintenance (Jarzen and Hogsette 2008, Taylor and Berkebile 2008), both sexes require blood meals for reproduction and longevity (Jones et al. 1992). Preferred breeding media are decaying fibrous plant materials, such as hay (Broce et al. 2005). Within zoological parks, hosts may include practically any accessible animal (e.g., sheep, goats, cows, camels, equines, primates, canids, and felids) (Hogsette and Farkas 2000). In many animals, e.g. cheetahs and wolves, stable fly feeding creates open lesions on the ear tips, typical of the damage seen with dogs (Farkas and Gyurcsó 2006). Humans and animals can be bitten when stable flies are present in large numbers (Rugg 1982). Although stable flies are known to be a problem in zoological parks (Hogsette and Farkas 2000), we are only familiar with the study by Rugg (1982) in Australia. If the seasonality and distribution of stable flies in zoological parks were known, this could facilitate control efforts. Alsynite fiberglass traps (AFTs) have been the standard trap used to survey and manage stable fly populations for a number of years (Hogsette and Ruff 1990). These traps are made of corrugated Alsynite fiberglass formed into cylinders (Broce 1988) and covered with transparent adhesive-coated sleeves. Traps are typically placed between 30-90 cm above the ground and as close as possible to target animal sites selected for evaluation. AFTs reflect light in the ultraviolet (UV) range (~360 nm) that is visible and attractive to S. calcitrans (Agee and Patterson 1983, Hogsette 2008). Blue-black cloth targets were adapted from Nzi traps developed in Africa to attract and capture tsetse flies (Glossina spp.) (Foil and Younger 2006), which transmit trypanosomes that cause sleeping sickness in humans and Nagana in animals. S. calcitrans are attracted to and will land preferentially on blue/black cloth targets (Mihok et al. 1995, Mihok 2002). Flies remain on targets for an average of 30 s which is long enough to acquire a lethal dose if targets have been treated with lambda-cyhalothrin (Foil and Younger 2006). The blue-black color contrast may mimic natural forest edges where stable flies alight to rest and digest their blood meals; S. calcitrans are also attracted to the blue/black fabric combinations because the fabric reflects light in the UV range (Mihok et al. 2006). Pesticide-impregnated blue/black cloth targets have been evaluated as management devices (Foil and Younger 2006), but blue/black cloth targets have not been evaluated after being modified into sticky traps for capturing S. calcitrans. The primary objective of this study was to evaluate the efficacy of blue-black cloth targets modified into sticky traps (BCTs) to capture S. calcitrans. BCTs were compared with AFTs at 10 selected sites for 15 weeks at a 12-ha zoological park near Washington, DC. Results elucidate relative trap efficacy, and stable fly distribution at the zoo and seasonality in northern Virginia.
Technical Abstract: Although this study was originally designed to compare the efficacy of 2 different stable fly traps within 10 sites at a 12-ha zoological park, seasonal and spatial population distribution data were simultaneously collected. The two traps included an Alsynite fiberglass cylindrical trap (AFT) and a blue-black cloth target modified into a cylindrical trap (BCT) utilizing the Alsynite fiberglass trap as its foundation. Both traps were covered with sticky sleeves to retain the attracted flies. Paired trap types were placed at sites that were between 20 and 100 m apart. Distance between trap pairs within sites ranged from 1-2 m, and was limited by exhibit design and geography. Both trap types utilize ultraviolet (UV) light reflected/refracted as an attractant to adult S. calcitrans. During this 15-wk study, AFTs captured significantly more stable flies than the BCTs at 8 of the 10 sites. Of the 12,557 stable flies found on the traps, 80 and 20% were captured by AFTs and BCTs, respectively. The most attractive trap site at the zoo was at the goat exhibit where the most stable flies were consistently captured throughout the study. This exhibit was 100 m from the other exhibits, next to a small lake, and adjacent to a field containing pastured exotic ungulates, rhea and ostrich. Stable fly populations peaked in early June then slowly decreased as the last trapping date approached. We believe this to be the first seasonality data collected at a zoological park. Results demonstrate the use of urban zoos by stable flies and the need to develop environmentally friendly stable fly management systems for zoos.