Artificial roosting structures (e.g. bat boxes) are widely used as conservation tools for many animals, including bats. Although it is relatively easy to monitor bat box temperatures, we know little about the effect of design on temperatures within a box. Box microclimate affects energy budgets and physiological processes and, thus, suitability as a roost. Optimal temperature varies during the period when reproductive females aggregate to rear pups; warm roosts enhance pup development during gestation and lactation, while cool roosts facilitate energy savings by torpor, which is often important during post‐lactation. To better understand the relation of design to internal temperature, we simultaneously compared 20 box designs (19 variations of a rocket box and one three‐chamber flat box) in an open site, May to September 2018. We measured temperatures at the top, middle and bottom of each box and tallied counts of daytime and nighttime cool (≤30°C; TCOOL), permissive (30.1–39.9°C; TPERM) and stressful (≥40°C; TSTRS) temperature observations. We also measured temperature, solar radiation and wind speed at the site. We used generalized linear models with negative binomial distributions to test the effects of design, environmental variables and their interactions. Adding an external jacket or decreasing ventilation increased daytime and nighttime counts of TPERM. Increasing box volume (i.e. lengthening box by 50%) also positively affected daytime counts of TPERM, whereas decreasing box volume (by 50%) had the opposite effect. Adding an external water jacket was the only modification we tested that decreased counts of TCOOL at night. Counts of TSTRS were elevated by warmer, sunnier and less windy conditions outside, but these effects were lessened by increasing roof shading or reflectivity, adding ventilation or external jackets, or decreasing box volume. These results inform the development and implementation of novel bat box designs as conservation and management tools for maternal colonies of bats, with consideration for the effects of weather on internal temperatures.

Bat box microclimates vary spatially and temporally in temperature suitability. This heterogeneity subjects roosting bats to a variety of thermoregulatory challenges (e.g. heat and cold stress). Understanding how different bat box designs, landscape placements, weather and bat use affect temperature suitability and energy expenditure is critical to promote safe and beneficial artificial roosting habitat for species of conservation concern. From April to September 2019, we systematically deployed 480 temperature dataloggers among 40 rocket box style bat boxes of 5 designs and regularly monitored bat abundance. We used bioenergetic models to assess energy costs for endothermic and heterothermic bats and modelled the overheating risk for each box as a function of design, placement, bat abundance and weather. For endothermic bats, predicted daily energy expenditure was lower for solar-exposed placements, large group sizes and a box design with enhanced thermal mass. For heterothermic bats, shaded landscape placements were the most energetically beneficial and bat box design was not important, because all designs generally offered microclimates suitable for torpor use at some position within the box. Overheating risk was highest for solar-exposed landscape placements and for designs lacking modifications to buffer temperature, and with increasing bat abundance, increasing ambient temperature and slower wind speeds. The external water jacket design, with the greatest thermal mass, concomitantly decreased overheating risk and endothermic energy expenditure. By assessing bat box suitability from two physiological perspectives, we provide a robust method to assess the conservation value of bat box design and placement strategies. We recommend future studies examine how changing thermal mass and conductance can be used to diminish overheating risk while also enhancing the effects of social thermoregulation for bat box users.

1. Infection often changes an animal's motivation or ability to forage, which should alter rates of contact with uninfected hosts. However, links are likely complex and remain poorly understood. Here, we explore relationships among infection, foraging decisions and contact rates and how these could interact with ecological factors to drive pathogen transmission.2. Under optimal foraging theory, animals should gather the highest quality resources from a patch, leaving only once the cost of continued foraging outweighs the amount of energy gained. However, the ability to locate and evaluate resources will vary with many factors, including disease, temperature and habitat fragmentation. Although modelling suggests that such variation in foraging decisions can alter contact rates among infected and uninfected hosts, and thus transmission and evolution of infectious agents, empirical studies have only begun to test the direction and strength of such relationships.3. We propose that foraging behaviour will often change with infection, thereby affecting contact rates, because of sickness behaviours, self-medication, parasite manipulation of the host and nonadaptive behavioural responses to infection. We recommend that future studies empirically test how such associations vary with ambient temperature and habitat fragmentation, as human activity continues to alter these environmental pressures. Furthermore, we suggest that such relationships among infection, foraging and environmental factors could help shape not only population-level disease dynamics, but also surrounding ecological communities. 4. By revealing how environmental factors impact such links, we can improve our understanding and prediction of animal disease dynamics in the face of changing ecosystems.