Freshwater alewives have been shown to be quite sensitive to cold water, and evidence exists to suggest that entire year classes have died in severe winters. Although a number of factors influence alewife survival rates, it is likely that overwinter mortality is substantial in most years. In spite of the apparent importance of overwinter mortality, estimates of overwinter mortality rates for th...

1. Overwinter mass loss can reduce energetic requirements in mammals (Dehnel's phenomenon). Alternatively, mass loss can result from food limitation or high predation risk. 2. We use data from fertilizer, food-supplementation and predator-exclusion experiments in the Yukon during a population cycle from 1986 to 1996 to test the causes of overwinter mass loss by snowshoe hares (Lepus americanus)...

Meadow jumping mice (Zapus hudsonius) reduce their metabolism substantially during hibernation and use stored fat reserves for overwinter energy needs. Preble’s meadow jumping mouse (Z. h. preblei; PMJM) occurs along the Front Range of Colorado, north into southeastern Wyoming, and is listed as a threatened species under the Endangered Species Act because of the conversion and degradation of ri...

Winter survival of organisms has a crucial effect on their fitness in a seasonal environment. We tested whether overwinter survival of male water striders, Aquarius najas (De Geer) (Heteroptera: Gerridae), is associated with the time of season they leave the water for winter diapause. This was performed by comparing parameters of males leaving the water at the beginning of autumn and 1 month la...

Recent hot droughts in California resulted ponderosa pine (Pinus ponderosa) mortality attributed to drought and western beetle (WPB, Dendroctonus brevicomis). While alone can cause tree death, direct warming effects on WPB are a contributing factor. Research generation timing (voltinism), however, is lacking. We monitored attacks adult emergence at two sites developed degree-day model from fiel...

Nematode multiplication rates Pf/Pi and overwinter survivorship (Pi2/Pfl) for Meloidogyne incognita were both adequately described by negative exponential models, indicating density dependence in each case. Density dependence of the multiplication rates is mediated by resource limitation and host damage; in survivorship rates it may be mediated by limitation of stored reserves or prevalence of ...

Seasonal multiplication and overwinter survival are density-dependent in Heterodera glycines. At low to moderate population densities, the nematode is capable of large population increases on susceptible soybean cultivars and high rates of oversummer or overwinter survival in the absence of a host. To improve estimates of H. glycines multiplication and survival rates, egg densities were monitor...

—Overwinter mortality is an important force structuring year-class strength of many fishes. Conventional wisdom is that overwinter mortality is primarily caused by starvation; however, recent research has demonstrated that piscivores continue to feed during winter and may also contribute to overwinter mortality of their prey populations. We conducted experiments in ten 0.04-ha earthen ponds in ...

Nematode multiplication rates Pf /Pi and overwinter survivorship (Pi2/Pfl) for Meloidogyne incognita were both adequately described by negative exponential models, indicating density dependence in each case. Density dependence of the multiplication rates is mediated by resource limitation and host damage; in survivorship rates it may be mediated by limitation of stored reserves or prevalence of...

Field experiments in the subtropical Lower Rio Grande Valley of Texas were conducted to determine the extent of adult boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), dispersal from cotton, Gossypium hirsutum L., fields during harvest operations and the noncotton-growing ("overwinter") period between 1 September and 1 February. Using unbaited large capacity boll weev...