Thermoregulatory ability and mechanism do not differ consistently between neotropical and temperate butterflies

Abstract

Climate change is a major threat to species worldwide, yet it remains uncertain whether tropical or temperate species are more vulnerable to changing temperatures. To further our understanding of this, we used a standardised field protocol to (1) study the buffering ability (ability to regulate body temperature relative to surrounding air temperature) of neotropical (Panama) and temperate (the United Kingdom, Czech Republic and Austria) butterflies at the assemblage and family level, (2) determine if any differences in buffering ability were driven by morphological characteristics and (3) used ecologically relevant temperature measurements to investigate how butterflies use microclimates and behaviour to thermoregulate. We hypothesised that temperate butterflies would be better at buffering than neotropical butterflies as temperate species naturally experience a wider range of temperatures than their tropical counterparts. Contrary to our hypothesis, at the assemblage level, neotropical species (especially Nymphalidae) were better at buffering than temperate species, driven primarily by neotropical individuals cooling themselves more at higher air temperatures. Morphology was the main driver of differences in buffering ability between neotropical and temperate species as opposed to the thermal environment butterflies experienced. Temperate butterflies used postural thermoregulation to raise their body temperature more than neotropical butterflies, probably as an adaptation to temperate climates, but the selection of microclimates did not differ between regions. Our findings demonstrate that butterfly species have unique thermoregulatory strategies driven by behaviour and morphology, and that neotropical species are not likely to be more inherently vulnerable to warming than temperate species.

Traumatic brain injury extending to the striatum alters autonomic thermoregulation and hypothalamic monoamines in recovering rats

“…An explanation for the increase in temperature in the sham and TBI groups between days 8 and 9 post-injury may be related to a variation in the ambient temperature. It is well known that small-scale temperature variation can play an important role in species’ thermal adaptation and can magnify the effects of increasing temperatures ( Mota-Rojas et al, 2021 ; Verduzco-Mendoza et al, 2021a ; Laird-Hopkins et al, 2023 ). It is possible that the temperature increase observed in both the injured and sham groups during this period was a response to ambient temperature variation, a result of thermal adaptation ( Mota-Rojas et al, 2021 ).…”

Regional differences in thermoregulation between two European butterfly communities

“…To study the relative importance of behaviour and microclimate for thermoregulation, we used the same indices as Bladon et al (2020) and Laird-Hopkins et al (2023) (Figure 1). The Index of Postural Thermoregulation (IPT) is the difference between thoracic temperature and microclimate temperature, that is the extent to which body temperature is elevated above microclimate temperature.…”

“…While Bladon et al (2020) compared buffering ability across a whole community, it is not clear if their results are generalisable to species outside that community or to populations of the same species living in other environments. On the other hand, Laird-Hopkins et al (2023) compared buffering abilities between temperate and neotropical butterflies, but with no species in common between the two communities. Therefore, no latitudinal comparisons of thermoregulation mechanisms across butterfly communities with similar species have been conducted, despite their potential to inform about tolerance to increasing temperatures.…”