Author
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Taylor, David |
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Berkebile, Dennis |
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Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/6/2010 Publication Date: 4/8/2011 Citation: Taylor, D.B., Berkebile, D.R. 2011. Phenology of stable fly (Diptera: Muscidae) larvae in round bale hay feeding sites in Eastern Nebraska. Environmental Entomology. 40: 184-193. Interpretive Summary: The manure mixed with hay found around sites where large round hay bales have been fed to cattle during the winter provides an excellent habitat for the development of stable fly maggots. We examined the seasonal pattern of adult stable fly emergence from these sites and compared that to the seasonal pattern of adult stable fly populations to determine the seasonal contributions of flies developing in hay feeding sites to overall biting adult stable fly populations. Adult stable flies were collected several weeks before they began to emerge from the hay feeding sites in the spring indicating that the first stable flies observed in the spring of each year are coming from habitats other than the winter hay feeding sites. Peak fly production in the hay feeding sites coincided with peak adult populations in June and July indicating that winter hay feeding sites are primary sources of biting stable flies during those months. Stable fly production in the hay feeding sites dropped to very low levels in late July and remained low for the rest of the year. Adult fly populations decreased slightly, but then rebounded to high levels in September through October. As with the very early season flies, these late season flies did not develop in hay feeding sites and therefore came from other, yet to be identified, larval habitats. Decomposition of the manure and hay substrate rendering it unsuitable for stable fly development appears to be the primary reason stable flies do not develop in the sites later in the year; weather conditions, temperature and precipitation, do not appear to be involved. Technical Abstract: The temporal and spatial patterns of adult stable fly, Stomoxys calcitrans (L.), emergence from six sites where large round baled hay had been provided to pastured cattle as winter feed were studied using emergence traps. The substrate at these sites, consisting of waste hay mixed with bovine manure and urine, provided an excellent developmental habitat for immature stable flies. Stable flies were the most frequently collected fly emerging from these sites with a yearly average of 1,581 emerging per square meter. Stable fly emergence from these sites began in early May (235 annual accumulated Day-Degree 10° C [DD10]), peaked in late June and early July (400-900 DD10) and then dropped to very low levels in late July (>900 DD10). The temporal pattern of stable fly emergence from the hay feeding sites differed from that of adult populations measured with sticky traps. Adult populations increased in the spring before significant emergence from the hay feeding sites was observed, dipped in mid-summer soon after the hay feeding sites became nonproductive, and then rebounded in the late summer when emergence from the hay feeding sites was very low. The drop in productivity of the hay feeding sites appeared to be due to endogenous factors associated with decomposition of the substrate rather than temperature or precipitation. Winter hay feeding sites appear to be primary sources of stable flies during the early summer, however, they are not responsible for late summer and fall stable fly populations. Overall, the inner most 2 meter annulus of the hay feeding sites was the most productive, however, spatial variation among sites was observed. The sex ratio of emerging flies did not differ from 1:1 and the temporal pattern of emergence was similar for males and females. Although several other species of flies were collected emerging from the hay feeding site substrate, house flies (Musca domestica L.) were notably absent. |
