Feeding Strategies of the Little Brown Bat, Myotis Lucifugus, in Southern New Hampshire

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.Abstract. Feeding strategies of the little brown bat, Myotis lucifugus, were investigated in southern New Hampshire USA from early May through late August 1974. Nightly food consumption was estimated by comparing mean prefeeding body weights with postfeeding weights taken as individuals returned to the roost from their first feeding period (at 2200 to 2400 h) and from a subsequent foraging period (at 0330 to 0500 h). Pregnant bats consumed an average of 2.5 g of insects (2.72 kJ/g prefeeding body weight) nightly, lactating females ate 3.7 g (4.23 kJ/g), and juveniles ingested 1.8 g (2.47 kJ/g). Increased food consumption in lactating bats accommodated reproductive energy demands and was facilitated by rising food availability. Increasing levels of independent food consumption in juveniles accompanied weaning.Fecal analysis revealed that diets of individual bats were diverse. All available insects 3 to 10 mm in body length were accepted as food items. Nematoceran Diptera were by far the most common insects taken in light-trap samples, and constituted a major portion of the diet throughout the summer. Coleoptera, Trichoptera, Lepidoptera, Ephemeroptera, and Neuroptera were also consumed in appreciable numbers.Comparison of dietary composition with prey availability indicates that pregnant bats consumed 3-10 mm prey in approximate proportions encountered during June, when insect availability was low and unpredictable. However, lactating, postlactating, and nonreproductive Y Y exhibited more selective feeding in July, when insects were more abundant. This increase in selectivity reflected exploitation of beetles and mayflies, which were uncommon in trap samples. In August, juveniles approximated random feeding patterns, as they learned to forage. We suggest that increased resource availability allowed selective feeding in adult bats during July, as predicted by prey selection models. However, reduced discriminatory abilities may prevent similar levels of prey selection in juveniles.

Spatiotemporal and demographic variation in the diet of New Zealand lesser short‐tailed bats (Mystacina tuberculata)

“…In some bats, juveniles forage in more open areas due to poor flying skills and likely as a result have different diets to adults (Adams, 1996, 1997; Hamilton & Barclay, 1998; Rolseth et al., 1994). As a result of their poor flying skills, juvenile bats may also capture fewer prey items than adults during the same foraging times (Anthony & Kunz, 1977). Yearling North‐western Crows ( Corvus caurinus ) select a broader range of prey sizes than do adults (Richardson & Verbeek, 1987), and this pattern holds true for some bats (Borkin & Parsons, 2011; Hamilton & Barclay, 1998; Salsamendi et al., 2008).…”

“…The high energetic cost of pregnancy and lactation is more likely to affect foraging strategies compared to males (Kunz, Whitaker, & Wadanoli, 1995; Swift, Racey, & Avery, 1985; Wilkinson & Barclay, 1997). Lactating little brown bats ( Myotis lucifugus ) have narrower diet breadth than other demographics as they are likely to form a “search image” to improve foraging efficiency and increase selectivity (Anthony & Kunz, 1977). Additionally, even when other prey types are available, lactating Mexican free‐tailed bats ( Tadarida brasiliensis ) maintain a narrow diet likely due to water balance requirements (Whitaker et al., 1996).…”

Energy Allocation in Mammalian Reproduction

“…In bats, even though the total energy expenditure during lactation may increase by 20-40% (see Anthony and Kunz, 1977;Kunz, 1987), females may shift energy expenditure from maintenance metabolism, via relaxation of homeothermy, to lactation, thus avoiding or minimizing increased food consumption. In brown long-eared bats {Plecotus auritus) the rate of increase in both absolute energy expenditure and expenditure relative to basal metabolism were similar during pregnancy and lactation (Racey and Speakman, 1987).…”

Heterothermy and the Use of Torpor by the Bat Eptesicus fuscus (Chiroptera: Vespertilionidae): A Field Study

“…The Ta also affects prey availability (e.g., Anthony and Kunz 1977;Racey and Swift 1985) reflected by foraging times (fig. 4).…”