Local Infestation or Long-Distance Migration? The Seasonal Recolonization of Dairy Farms by <I>Stomoxys calcitrans</I> (Diptera: Muscidae) in South Central Ontario, Canada

Abstract

Stable fly (Diptera: Muscidae) populations in south central Ontario, Canada, first occur on dairy farms in late spring, grow exponentially throughout the summer, and are frozen back each autumn. We examined the extent of overwinter persistence on 22 dairy farms in a 55- by 60-km region north of Lake Ontario that spans four climatic zones. Our overwintering sampling of larval habitat identified three farms located in the southern section of the study region as potential overwintering refugia. Using sticky trap catches to identify the timing of first spring appearance at each farm, we then tested two models of how local farm populations are reestablished annually: 1) stable flies disperse from local climatic refuges and colonize neighboring farms (the local source model); and 2) stable flies are carried into the study region by frontal weather systems (the distant source model). The timing of when stable flies first occurred at these farms supported a local source of dispersing colonists from a small proportion of local refuge farms. We discuss our results in terms of how yearly fluctuation in climate would affect refuge farm density in the region and how this, in turn, would shift the recolonization dynamic. Implications for controlling stable flies also are discussed.

Population Dynamics of Stable Flies Stomoxys calcitrans (Diptera: Muscidae) at an Organic Dairy Farm in Denmark Based on Mark-recapture With Destructive Sub-sampling

“…Males and young females especially have been reported to leave when population densities are high (Scholl 1986, Hogsette et al 1989, which can be attributed to increasing levels of intraspeciÞc competition. However, Beresford and Sutcliffe (2009) claim that spring dispersal of female stable ßies from farms in south central Ontario, Canada, was not densitydependent.…”

Phenology of Stable Fly (Diptera: Muscidae) Larvae in Round Bale Hay Feeding Sites in Eastern Nebraska

“…Overwintering stable ßy larvae have been observed in heat generating substrates such as silage (Scholl et al 1981) and occasional adults have be observed on traps, even in mid winter (Berkebile et al 1994). Continuous breeding, possibly in climate controlled environments such as dairies or heated barns (Beresford and Sutcliffe 2009), and overwintering are a potential sources for the early season ßies, however, Þnding overwintering ßies has proven to be very difÞcult. Jones et al (1999) postulated that stable ßies passively migrate long distances on frontal systems, permitting southern populations to recolonize the northern portions of their range each year.…”

Field Measurements of Stable Fly (Diptera: Muscidae) Demography, Fecundity, and Survival Based on Daily Trap Catches at a Beef Farm in Southern Ontario Over a 5-yr Period

“…Our use of a 10ЊC base for development is based on PruessÕs (1983) recommendation for a standardized base to be used in pest management (e.g., Beresford and Sutcliffe 2009b). We used weather station data, which is obtained from a Stevenson screen in which thermometers are set 1.2Ð2 m high (Barry and Chorley 1976).…”