Data from: The adaptive value of gluttony: predators mediate the life history trade-offs of satiation threshold

Animals vary greatly in their tendency to consume large meals. Yet, whether or how meal size influences fitness in wild populations is infrequently considered. Using a predator exclusion, marked-recapture experiment, we estimated selection on the amount of food accepted during an ad libitum feeding bout (hereafter termed "satiation threshold") in the wolf spider Schizocosa ocreata. Individually marked, size-matched females of known satiation threshold were assigned to predator exclusion and predator inclusions treatments and tracked for a 40 day period. We also estimated the narrow sense heritability of satiation threshold using dam on female offspring regression. In the absence of predation, high satiation threshold was positively associated with larger and faster egg case production. However, these selective advantages were lost when predators were present. We estimated the heritability of satiation threshold to be 0.56. Taken together, our results suggest that satiation threshold can respond to selection and begets a life history trade-off in this system: high satiation threshold individuals tend to produce larger egg cases but also suffer increased susceptibility to predation

Patterns of Bat Distribution and Foraging Activity in a Highly Urbanized Temperate Environment

<div><p>Understanding how to manage biodiversity in urban areas will become increasingly important as density of humans residing in urban centers increases and urban areas expand. While considerable research has documented the shifts in biodiversity along urbanization gradients, much less work has focused on how characteristics of dense urban centers, effectively novel environments, influence behavior and biodiversity. Urban bats in San Francisco provide an opportunity to document changes in behavior and biodiversity to very high-density development. We studied (1) the distribution and abundance of bat foraging activity in natural areas; and (2) characteristics of natural areas that influence the observed patterns of distribution and foraging activity. We conducted acoustic surveys of twenty-two parks during 2008–2009. We confirmed the presence of four species of bats (<i>Tadarida brasiliensis</i>, <i>Myotis yumanensis</i>, <i>Lasiurus blossevillii</i>, and <i>M</i>. <i>lucifugus</i>). <i>T</i>. <i>brasiliensis</i> were found in all parks, while <i>M</i>. <i>yumanensis</i> occurred in 36% of parks. Results indicate that proximity to water, park size, and amount of forest edge best explained overall foraging activity. Proximity to water best explained species richness. <i>M</i>. <i>yumanensis activity</i> was best explained by reduced proportion of native vegetation as well as proximity to water. Activity was year round but diminished in December. We show that although bats are present even in very densely populated urban centers, there is a large reduction in species richness compared to that of outlying areas, and that most habitat factors explaining their community composition and activity patterns are similar to those documented in less urbanized environments.</p></div

Relative importance (and sign of relationship) of model variables for different measures of activity and species richness.

<p>Relative importance (and sign of relationship) of model variables for different measures of activity and species richness.</p

Model QAICc values and weights.

<p>Model QAICc values and weights.</p

Regional bat species pool for San Francisco and surrounding counties.

<p>Regional bat species pool for San Francisco and surrounding counties.</p

Data from: Weather-driven dynamics in a dual-migrant system: moths and bats

Animal migrations generate large spatial and temporal fluctuations in biomass that provide a resource base for many predator-prey interactions. These interactions are often driven by continent-scale weather patterns and are difficult to study. Few studies have included migratory animals on more than a single trophic level or for periods spanning multiple entire seasons. We tracked migrations of three species of agricultural pest noctuid moths over the 2010-2012 autumn seasons as the moths traveled past a large colony of migratory Brazilian free-tailed bats (Tadarida brasiliensis) in Texas. Increases in moth abundance, mass of bats, and duration of bat activity outside of the cave were correlated with passage of cold fronts over the study area and related increases in northerly wind. Moth responses to weather patterns varied among species and seasons, but overall moth abundances were low in late summer and spiked after one or more cold front passages in September and October. Changes in bat mass and behavior appear to be consequences of bat migration, as cave use transitioned from summer maternity roost to autumn migratory stopover sites. Weather-driven migration is at considerable risk from climate change, and bat and moth responses to that change may have marked impacts on agricultural systems and bat ecosystem services

gluttony.xls

gluttony.xl

Chapter 8. Insect migrations and the ecology, behavior, and population dynamics of bats

Insectivorous bats consume a huge diversity of prey, with patterns in prey consumption resulting from bat responses to the ecology and availability of insects. Insect migrations involve huge spatial and temporal inputs of energy and nutrients that provide dietary bonanzas for bats. Although insect migrations are often predictable, overlap with major life history features of bats, and significantly influence bat ecology, behavior, and population dynamics, insect migrations have received little notice from bat biologists. Correspondingly, despite the ubiquity, scale, and ecological significance of insect migrations, the migratory behavior of most insects remains poorly understood. Insectivorous bats can provide crucial information on insect movements. Because many migratory insects are agricultural pests, this information is important to crop protection and a better understanding of the ecosystem services of bats. We discuss the needs and opportunities for productive research collaboration between insect migration researchers and bat biologist

2010 Data

Contains raw data from the 2010 field season, including bat, moth, and weather data