Insights into the distribution and ecology of the funnelweb spider Macrothele calpeiana in Portugal

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  Insights into the distribution and ecology of the funnelweb spider Macrothele calpeiana in Portugal Abstract Biodiversity surveys are critical to prevent decline and extinction of ill-/unknown species through timely conservation action. This is particularly relevant when the species are neither iconic nor flagships, therefore lessening the potential for accessing conservation means, such as in the case of the mygalomorph spider Macrothele calpeiana. The species is endemic to southern Iberia but its distribution and ecology is barely documented in Portugal. Therefore, we made a comprehensive survey throughout its estimated range in the south of the country. The species is spread unevenly and patchily throughout low mountainous terrain in south/southwest Portugal, preferably along shale/ greywacke/clay roadside banks. It seems rare in the surrounding limestone area to the south and absent from the peneplain to the north. The webs were found in groups averaging 10.0±15.2 webs/site a...

Temperature-induced changes in lipids and fatty acids in spiders

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Temperature-induced changes in lipids and fatty acids in spiders

Abstract

Temperature variations significantly impact the development, reproduction, and physiological functioning of organisms, particularly in ectothermic species, where physiological adaptations are crucial to maintain metabolic processes under changing thermal conditions. Alterations in lipid composition play a key role in preventing the malfunction of lipid systems when exposed to extreme temperatures. We analysed the lipid and fatty acid composition of two key organs, the midgut diverticula and muscle, of the spider Polybetes pythagoricus, following a 20-day acclimatization to 1, 4, 25, and 35°C. In adult muscle acclimatized to low temperatures, we observed an increase in phosphatidylcholine and cholesterol, with a corresponding decrease in phosphatidylethanolamine. In juvenile midgut diverticula, triacylglycerol levels decreased at the highest temperature, while phosphatidylcholine increased in muscle at low temperatures. Regarding fatty acids, lower temperatures generally led to an increase in unsaturated fatty acids (16:1 and 18:1) and a decrease in saturated fatty acids (17:0 and 20:0). We conclude that thermal acclimatization in P. pythagoricus induces previously undescribed changes in lipid and fatty acid composition. These variations are diverse and, in some cases, organ-specific or dependent on developmental stage.

Gabriel Molina, Aldana Laino, Luciano Peralta, Carlos Fernando Garcia "Temperature-induced changes in lipids and fatty acids in spiders," Arachnology, 20(5), 709-716, (8 July 2026)