scholarly journals Microclimate buffering and thermal tolerance across elevations in a tropical butterfly

2019 ◽  
Author(s):  
Gabriela Montejo-Kovacevich ◽  
Simon H. Martin ◽  
Joana I. Meier ◽  
Caroline N. Bacquet ◽  
Monica Monllor ◽  
...  

AbstractMicroclimatic variability in tropical forests plays a key role in shaping species distributions and their ability to cope with environmental change, especially for ectotherms. Yet, currently available climatic datasets lack data from the forest interior and our knowledge of thermal tolerance among tropical ectotherms is limited. To tackle this, we studied natural variation in the microclimate experienced by a tropical genus of butterflies (Heliconius sp.) along their Andean range across a single year. We found that the forest strongly buffers temperature and humidity in the understory, especially in the lowlands where temperatures are more extreme. There were systematic differences between our yearly records and macroclimate databases (WorldClim2), with lower interpolated minimum temperatures and maximum temperatures higher than expected. We then assessed thermal tolerance of ten Heliconius butterfly species in the wild and showed that populations at high elevations had significantly lower heat tolerance than those at lower elevations. However, when we reared populations of the widespread H. erato from high and low elevations in a common-garden environment, the difference in heat tolerance across elevations was reduced, indicating plasticity in this trait. Microclimate buffering is not currently captured in publicly available datasets but could be crucial for enabling upland shifting of species sensitive to heat such as highland Heliconius. Plasticity in thermal tolerance may alleviate the effects of global warming on some widespread ectotherm species, but more research is needed to understand the long-term consequences of plasticity on populations and species.Summary statementTropical forests along the Andes were found to greatly buffer climate. The butterflies inhabiting high elevations were less thermally tolerant but not when reared in common-garden conditions, indicating plasticity.

2020 ◽  
Vol 16 (1) ◽  
pp. 20190716 ◽  
Author(s):  
Alex R. Gunderson ◽  
Amélie Fargevieille ◽  
Daniel A. Warner

Extreme heat events are becoming more common as a result of anthropogenic global change. Developmental plasticity in physiological thermal limits could help mitigate the consequences of thermal extremes, but data on the effects of early temperature exposure on thermal limits later in life are rare, especially for vertebrate ectotherms. We conducted an experiment that to our knowledge is the first to isolate the effect of egg (i.e. embryonic) thermal conditions on adult heat tolerance in a reptile. Eggs of the lizard Anolis sagrei were incubated under one of three fluctuating thermal regimes that mimicked natural nest environments and differed in mean and maximum temperatures. After emergence, all hatchlings were raised under common garden conditions until reproductive maturity, at which point heat tolerance was measured. Egg mortality was highest in the warmest treatment, and hatchlings from the warmest treatment tended to have greater mortality than those from the cooler treatments. Despite evidence that incubation temperatures were stressful, we found no evidence that incubation treatment influenced adult heat tolerance. Our results are consistent with a low capacity for organisms to increase their physiological heat tolerance via plasticity, and emphasize the importance of behavioural and evolutionary processes as mechanisms of resilience to extreme heat.


2020 ◽  
Author(s):  
Juan C. Diaz-Ricaurte ◽  
Filipe C. Serrano ◽  
Estefany Caroline Guevara-Molina ◽  
Cybele Araujo ◽  
Marcio Martins

AbstractEnvironmental temperatures are a major constraint on ectotherm abundance and diversity, influencing their distribution and natural history. Comparing thermal tolerances with environmental temperatures is a simple way to estimate thermal constraints on species distributions. We investigate the potential effects of thermal tolerance on anuran local (habitat) and global distribution patterns and associated behavioral responses. We tested for differences in Voluntary Thermal Maximum of two sympatric frog species of the genus Physalaemus in the Cerrado ecoregion. For each species, we constructed models to assess the effects of period of day, duration of experiment, initial body mass, initial body temperature and heating rate on the VTMax. We mapped the difference between VTMax and maximum daily temperature (VTMax - ETMax) for each occurrence point. Physalaemus nattereri had a significantly higher VTMax than P. cuvieri. For P. nattereri, the model including only period of day was chosen as the best to explain variation in the VTMax. For P. cuvieri, no model was selected as best to predict VTMax. The VTMax - ETMax values were significantly different between species, with P. nattereri mostly found in localities that attain maximum temperatures lower than its VTMax and P. cuvieri showing the reverse pattern. Regarding habitat use, we found P. cuvieri to be slightly more abundant in open habitats than in non-open habitats, whereas P. nattereri shows the reverse pattern. The difference in VTMax values between these two species might be related to their different body sizes, but additionally might reflect their natural history, especially the way they use their habitats, and phylogenetic constraints (the species studied are in different clades within Physalaemus). Our study indicates that differences in behavioral thermal tolerance may be important in shaping local and regional distribution patterns. Furthermore, small-scale habitat use might reveal a link between behavioral thermal tolerance and natural history strategies.


Author(s):  
Kazuho Isono ◽  
Ryo Tsukimoto ◽  
Satoshi Iuchi ◽  
Akihisa Shinozawa ◽  
Izumi Yotsui ◽  
...  

Abstract Plants are often exposed not only to short-term (S-) heat stress but also to diurnal long-term (L-) heat stress over several consecutive days. To reveal the mechanisms underlying L-heat stress tolerance, we here used a forward genetic screening for sensitive to long-term heat (sloh) mutants and isolated sloh4. The mutant was hypersensitive to L- but not S-heat stress. The causal gene of sloh4 was identical to MIP3 encoding a member of the MAIGO2 (MAG2) tethering complex, which is composed of the MAG2, MIP1, MIP2, and MIP3 subunits and is localized at the endoplasmic reticulum (ER) membrane. Although sloh4/mip3 was hypersensitive to L-heat stress, the sensitivity of the mag2-3 and mip1–1 mutants was similar to that of the wild type. Under L-heat stress, the ER stress and the following unfolded protein response (UPR) were more pronounced in sloh4 than in the wild type. Transcript levels of bZIP60-regulated UPR genes were strongly increased in sloh4 under L-heat stress. Two processes known to be mediated by INOSITOL REQUIRING ENZYME1 (IRE1)—accumulation of the spliced bZIP60 transcript and a decrease in the transcript levels of PR4 and PRX34, encoding secretory proteins—were observed in sloh4 in response to L-heat stress. These findings suggest that misfolded proteins generated in sloh4 under L-heat stress may be recognized by IRE1 but not bZIP28, resulting in initiation of the UPR via activated bZIP60. Therefore, it would be possible that only MIP3 in MAG2 complex has an additional function in L-heat tolerance, which is not related to the ER–Golgi vesicle tethering.


2016 ◽  
Vol 30 (6) ◽  
pp. 903-912 ◽  
Author(s):  
Nicholas L. Payne ◽  
James A. Smith ◽  
Dylan E. Meulen ◽  
Matthew D. Taylor ◽  
Yuuki Y. Watanabe ◽  
...  

2018 ◽  
Vol 2 (1) ◽  
pp. 1-10
Author(s):  
Oscar Gonzalez

In Latin America, Pentecostal churches have an important presence in local Andean communities. I explored the opinions that rural people of the Pentecostal faith in the Peruvian Andes have on nature and conservation and tested the Evangelical principle of Creation Care as an effective method to approach them and get them interested in conservation issues. I attended special meetings of rural Pentecostal churches in Huanuco, Peru, in 2012 and 2013; the congregations allowed me to share the importance of nature conservation, and Creation Care facilitated this communication. I discuss the details of one of the events where I participated as an invited speaker to talk about nature conservation. For those who wish to foster a dialogue with Pentecostals and Evangelical residents of the Andes on the rationale for environmental stewardship, I recommend becoming familiar with the principle of Creation Care and looking for its application in specific environmental problems of the region.


2018 ◽  
Vol 115 (46) ◽  
pp. 11850-11855 ◽  
Author(s):  
S. Blair Hedges ◽  
Warren B. Cohen ◽  
Joel Timyan ◽  
Zhiqiang Yang

Tropical forests hold most of Earth’s biodiversity. Their continued loss through deforestation and agriculture is the main threat to species globally, more than disease, invasive species, and climate change. However, not all tropical forests have the same ability to sustain biodiversity. Those that have been disturbed by humans, including forests previously cleared and regrown (secondary growth), have lower levels of species richness compared with undisturbed (primary) forests. The difference is even greater considering extinctions that will later emanate from the disturbance (extinction debt). Here, we find that Haiti has less than 1% of its original primary forest and is therefore among the most deforested countries. Primary forest has declined over three decades inside national parks, and 42 of the 50 highest and largest mountains have lost all primary forest. Our surveys of vertebrate diversity (especially amphibians and reptiles) on mountaintops indicates that endemic species have been lost along with the loss of forest. At the current rate, Haiti will lose essentially all of its primary forest during the next two decades and is already undergoing a mass extinction of its biodiversity because of deforestation. These findings point to the need, in general, for better reporting of forest cover data of relevance to biodiversity, instead of “total forest” as defined by the United Nation’s Food and Agricultural Organization. Expanded detection and monitoring of primary forest globally will improve the efficiency of conservation measures, inside and outside of protected areas.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3112 ◽  
Author(s):  
Thomas Enriquez ◽  
Hervé Colinet

The spotted wing Drosophila,Drosophila suzukii, is a new pest in Europe and America which causes severe damages, mostly to stone fruit crops. Temperature and humidity are among the most important abiotic factors governing insect development and fitness. In many situations, temperature can become stressful thus compromising survival. The ability to cope with thermal stress depends on basal level of thermal tolerance. Basic knowledge on temperature-dependent mortality ofD. suzukiiis essential to facilitate management of this pest. The objective of the present study was to investigateD. suzukiibasal cold and heat tolerance. Adults and pupae were subjected to six low temperatures (−5–7.5 °C) and seven high temperatures (30–37 °C) for various durations, and survival-time-temperature relationships were investigated. Data showed that males were globally more cold tolerant than females. At temperature above 5 °C, adult cold mortality became minor even after prolonged exposures (e.g., only 20% mortality after one month at 7.5 °C). Heat tolerance of males was lower than that of females at the highest tested temperatures (34, 35 and 37 °C). Pupae appeared much less cold tolerant than adults at all temperatures (e.g., Lt50at 5° C: 4–5 d for adultsvs.21 h for pupae). Pupae were more heat tolerant than adults at the most extreme high temperatures (e.g., Lt50at 37 °C: 30 min for adultsvs.4 h for pupae). The pupal thermal tolerance was further investigated under lowvs.high humidity. Low relative humidity did not affect pupal cold survival, but it reduced survival under heat stress. Overall, this study shows that survival ofD. suzukiiunder heat and cold conditions can vary with stress intensity, duration, humidity, sex and stage, and the methodological approach used here, which was based on thermal tolerance landscapes, provides a comprehensive description ofD. suzukiithermal tolerance and limits.


Zootaxa ◽  
2019 ◽  
Vol 4585 (2) ◽  
pp. 295 ◽  
Author(s):  
DAN A. POLHEMUS ◽  
FREDY MOLANO ◽  
IRINA MORALES ◽  
FELIPE FERRAZ FIGUEIREDO MOREIRA ◽  
CARLA FERNANDA BURGUEZ FLORIANO

The new genus Altavelia Polhemus & Moreira (Heteroptera: Gerromorpha: Veliidae) includes seven species previously contained in the inveruglas group of Paravelia Breddin, 1898 and four new species from Colombia: A. altoandina Molano & Morales, A. antioquia Molano & Morales, A. montana Molano & Morales, and A. quindiana Molano & Morales. Additionally, A. amoena (Drake, 1957) is synonymized with A. flavomarginata (Hungerford, 1930). The genus is characterized by prominent setal tufts or sclerotized wing-like processes on the male proctiger; elongate body shape with long, slender legs; uniformly blackish forewings; antennal segment I longest; and the female abdomen with tergum VIII deflexed. Species in this genus occur at high elevations in the Andes Mountains with records from 1500 to 3600 m. A key is provided to all 11 species in the genus and new distributional records are presented for A. boliviana (Breddin, 1898), A. columbiensis (Hungerford, 1930), and A. flavomarginata.  


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Bert Van Bocxlaer ◽  
Claudia M. Ortiz-Sepulveda ◽  
Pieter R. Gurdebeke ◽  
Xavier Vekemans

Abstract Background Ecological speciation is a prominent mechanism of diversification but in many evolutionary radiations, particularly in invertebrates, it remains unclear whether supposedly critical ecological traits drove or facilitated diversification. As a result, we lack accurate knowledge on the drivers of diversification for most evolutionary radiations along the tree of life. Freshwater mollusks present an enigmatic example: Putatively adaptive radiations are being described in various families, typically from long-lived lakes, whereas other taxa represent celebrated model systems in the study of ecophenotypic plasticity. Here we examine determinants of shell-shape variation in three nominal species of an ongoing ampullariid radiation in the Malawi Basin (Lanistes nyassanus, L. solidus and Lanistes sp. (ovum-like)) with a common garden experiment and semi-landmark morphometrics. Results We found significant differences in survival and fecundity among these species in contrasting habitats. Morphological differences observed in the wild persisted in our experiments for L. nyassanus versus L. solidus and L. sp. (ovum-like), but differences between L. solidus and L. sp. (ovum-like) disappeared and re-emerged in the F1 and F2 generations, respectively. These results indicate that plasticity occurred, but that it is not solely responsible for the observed differences. Our experiments provide the first unambiguous evidence for genetic divergence in shell morphology in an ongoing freshwater gastropod radiation in association with marked fitness differences among species under controlled habitat conditions. Conclusions Our results indicate that differences in shell morphology among Lanistes species occupying different habitats have an adaptive value. These results also facilitate an accurate reinterpretation of morphological variation in fossil Lanistes radiations, and thus macroevolutionary dynamics. Finally, our work testifies that the shells of freshwater gastropods may retain signatures of adaptation at low taxonomic levels, beyond representing an evolutionary novelty responsible for much of the diversity and disparity in mollusks altogether.


2019 ◽  
Vol 374 (1778) ◽  
pp. 20190036 ◽  
Author(s):  
Jennifer Sunday ◽  
Joanne M. Bennett ◽  
Piero Calosi ◽  
Susana Clusella-Trullas ◽  
Sarah Gravel ◽  
...  

Linking variation in species' traits to large-scale environmental gradients can lend insight into the evolutionary processes that have shaped functional diversity and future responses to environmental change. Here, we ask how heat and cold tolerance vary as a function of latitude, elevation and climate extremes, using an extensive global dataset of ectotherm and endotherm thermal tolerance limits, while accounting for methodological variation in acclimation temperature, ramping rate and duration of exposure among studies. We show that previously reported relationships between thermal limits and latitude in ectotherms are robust to variation in methods. Heat tolerance of terrestrial ectotherms declined marginally towards higher latitudes and did not vary with elevation, whereas heat tolerance of freshwater and marine ectotherms declined more steeply with latitude. By contrast, cold tolerance limits declined steeply with latitude in marine, intertidal, freshwater and terrestrial ectotherms, and towards higher elevations on land. In all realms, both upper and lower thermal tolerance limits increased with extreme daily temperature, suggesting that different experienced climate extremes across realms explain the patterns, as predicted under the Climate Extremes Hypothesis . Statistically accounting for methodological variation in acclimation temperature, ramping rate and exposure duration improved model fits, and increased slopes with extreme ambient temperature. Our results suggest that fundamentally different patterns of thermal limits found among the earth's realms may be largely explained by differences in episodic thermal extremes among realms, updating global macrophysiological ‘rules’. This article is part of the theme issue ‘Physiological diversity, biodiversity patterns and global climate change: testing key hypotheses involving temperature and oxygen’.


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