Fowler Fallon E, Chirico Jan, Sandelin Broc A, Mullens Bradley A
Department of Entomology, University of California, Riverside, CA 92521, USA. Department of Entomology, North Carolina State University, Raleigh, NC 27695, USA.
Department of Virology, Immunobiology and Parasitology, National Veterinary Institute (SVA), Uppsala, Sweden.
J Med Entomol. 2015 Nov;52(6):1213-24. doi: 10.1093/jme/tjv123. Epub 2015 Aug 19.
The face fly (Musca autumnalis De Geer) and horn fly (Haematobia irritans ([L.])) were studied at the southern edge of the face fly's North American range, examining southern California geographic distribution, seasonal activity on cattle and in dung, and diapause. Face flies were common only at Pomona (34°03'N, 117°48'W). Other irrigated pastures, even those only slightly inland from Pomona, were probably too warm for face flies, due to a steep west (cooler) to east (warmer) temperature gradient. Horn flies were abundant at all sites. Adult densities on cattle, adults emerging from dung pats, and prevalence of fly-positive pats were assessed for both fly species throughout a year at Pomona. Summer adult horn fly densities of 500-2,000 flies per cow, or face fly densities of 3-10 flies per face, were common. Summer prevalence of face fly-positive pats and horn fly-positive pats was about 20-40% and 30-70%, respectively. Face fly adults diapaused from late October until late March and early April. Horn flies probably diapaused as pupae from late October or early November to early-mid March, although some emerged in winter. Experimental cohorts of October-emerging adult face flies were held in a representative overwintering site. They exhibited hypertrophied fat body and undeveloped oocytes, which are characteristics of diapause, and survived until the following spring. The dominant diapause cues in face and horn flies are probably photoperiod and temperature. Despite warm winter temperatures that would permit activity of both species, and despite relatively long winter day lengths, face flies and most horn flies still diapaused at this latitude.
在北美面蝇分布范围的南部边缘地区对面蝇（秋家蝇，Musca autumnalis De Geer）和角蝇（血蝇，Haematobia irritans ([L.])）进行了研究，调查了南加州的地理分布、在牛身上和粪便中的季节性活动以及滞育情况。面蝇仅在波莫纳（北纬34°03′，西经117°48′）较为常见。其他灌溉牧场，即使是那些距离波莫纳仅略靠内陆的牧场，可能由于存在从西（较凉爽）到东（较温暖）的陡峭温度梯度，对面蝇来说温度过高。角蝇在所有地点都数量众多。在波莫纳，全年对这两种蝇类评估了牛身上的成虫密度、从粪堆中羽化出的成虫以及蝇阳性粪堆的发生率。夏季每头牛身上角蝇成虫密度为500 - 2000只，或每只面部面蝇密度为3 - 10只，这很常见。夏季面蝇阳性粪堆和角蝇阳性粪堆的发生率分别约为20% - 40%和30% - 70%。面蝇成虫从10月下旬至3月下旬以及4月上旬进入滞育。角蝇可能从10月下旬或11月上旬至3月上旬至中旬以蛹的形式滞育，不过有些在冬季羽化。10月羽化的成年面蝇实验群体被放置在一个具有代表性的越冬地点。它们表现出脂肪体肥大和卵母细胞未发育，这是滞育的特征，并存活到次年春天。面蝇和角蝇中主要的滞育信号可能是光周期和温度。尽管冬季温度温暖足以使这两种蝇类活动，且冬季日照时间相对较长，但在这个纬度面蝇和大多数角蝇仍进入滞育。
