Development time, adult body weight and fecundity of female Trichonephila senegalensis spiders
Data files
Mar 25, 2021 version files 89.13 KB
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Data_Lissowsky_etal_2021.zip
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README_for_Data_Lissowsky_etal_2021.pdf
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Abstract
Variation in life history traits within a population is caused by genetic, maternal and environmental factors. We explore high variability in development time, adult body weight and fecundity in females of the sexually-size dimorphic spider Trichonephila senegalensis. While their mothers originated from two habitats – strongly seasonal Namibia and mildly seasonal South Africa, we reared F1 females under standardized laboratory conditions. We find that a considerable part of the variability in recorded life-history traits is caused by family-specific effects, comprising genetic, maternal and early environmental influences. Furthermore, we show population differences in development time, where females originating from Namibia matured within shorter periods than females from South Africa. Also, the relationship between development time and adult weight differs between the two populations, as a significant correlation is only found in females with Namibian origin. Against common wisdom, there was a weak overall correlation between adult weight and clutch mass. We also found that females make different life-history decisions under increasing than under decreasing daylengths that the females could have perceived through the windows. While a considerable part of variability in life history traits is family specific, we discuss how the between-population differences in life-histories and their trade-offs reflect adaptation to diverse habitats.
Methods
The spider species Trichonephila senegalensis of the family Nephilidae (Araneoidea; Kuntner et al., 2019), has a wide distribution across central and southern Africa. Lab populations were derived from collections of several adult females or eggsacs from sites in Namibia and South Africa in the years 2007, 2008, 2011, 2012, 2015, and 2017 by our research group.
The present dataset consists of data on females of the first lab generation, which were F1 descendants of unrelated mated females or eggsacs collected in the field (P-generation). Between 60 and 100 randomly selected spiderlings from all available matrilines (N=59) were raised to adulthood while keeping track of family background. All eggsacs and spiders were inspected regularly, recording
- the date on which the first spiderlings emerged from the eggsac,
- the date of the final moult, which corresponds to the maturity date,
- the adult weight, being the body weight on the day after maturation
- and the date as well as the weight of the first eggsac produced by the first lab generation
All spiders were raised under standardized conditions in the laboratory. They were kept at temperatures between 24 and 26°C, an artificial light-regime of 14:10 LD although natural light conditions were not excluded due to large windows on one side of the room. Thus, we did not fully control for the amount and duration of daylight exposure. To account for this factor, we added the variables daylength at hatching date (daylength HD) and daylength at eggsac (daylength ED) date to the table which included whether the hatching or the laying of the first eggsac occurred in times where daylength in Germany was increasing or decreasing. At this latitude, the length of the day increases between December 22nd and the 21st of June and starts to decrease on the 22nd until the 21st of December. We made the simplified assumption daylength to be increasing for the months January to June and decreasing in the period July to December.
For a further description of the variables contained in the present dataset please check "README_for_Data_Lissowsky_etal_2021".