Browsing by Subject "life-history"

Sort by: Order: Results:

Now showing items 1-3 of 3
  • Caterpillar Rearing Group (CRG), LepSoc Africa; Staude, Hermann; MacLean, Marion; Mecenero, Silvia; Pretorius, Rudolph J.; Oberprieler, Rolf G.; van Noort, Simon; Sharp, Allison; Sharp, Ian; Balona, Julio; Bradley, Suncana; Brink, Magriet; Morton, Andrew S.; Bodha, Magda J.; Collins, Steve C.; Grobler, Quartus; Edge, David A.; Williams, Mark C.; Sihvonen, Pasi (2020)
    We present an overview of the known host associations of larval Lepidoptera for southern Africa, based on a database of 11 628 rearings, including all Caterpillar Rearing Group (CRG) records and other published records. Rearings per Lepidoptera family show some bias in the rearing effort towards the more conspicuous families, ectophagous groups and non-detritus-feeders but in general follow species diversity. Recorded Lepidoptera host associations per host family for southern Africa are shown. Data analyses revealed the following general trends: of the 20 most reared species 13 are polyphagous; Fabaceae are the most utilised plant family with 2 122 associations, followed by Asteraceae (600), Malvaceae (564) and Anacardiaceae (476); 98.8 % of hosts are vascular plants; and of the 19 most utilised host species 18 are common trees or shrubs. We discuss possible reasons behind these trends, particularly the high utilisation of Fabaceae and the widespread use of trees and shrubs as hosts. We compare recorded host species numbers with species diversity for the 19 most recorded host families and discuss possible reasons for the low utilisation of four plant families with an exceptionally low percentage of Lepidoptera host species / plant host species diversity. All Lepidoptera families for which more than 100 rearings have been recorded (21 families) utilise one (or two in the case of Pyralidae, Nolidae and Hesperiidae) plant family exponentially more than any of the other families, with resulting histograms forming hyperbolic curves, as are typical of distributions of taxonomic assemblages in nature. We calculate an exponential factor to quantify this phenomenon and show that for all 21 Lepidoptera families one host family is utilised 6–33 times more than the average use of other host families. In this paper, the larvae and adults of 953 African, mostly South African, Lepidoptera species reared by the CRG between January 2016 and June 2019 are illustrated together with pertinent host information. 119 Lepidoptera-parasitoid associations are reported, comprising seven hymenopteran families and one dipteran family. With the current data release, larval host association records are now available for 2 826 Lepidoptera species in the southern African subregion, covering about 25 % of the described fauna.
  • Halali, Sridhar; Halali, Dheeraj; Barlow, Henry S.; Molleman, Freerk; Kodandaramaiah, Ullasa; Brakefield, Paul M.; Brattstrom, Oskar (2021)
    Phenotypic plasticity in heterogeneous environments can provide tight environment-phenotype matching. However, the prerequisite is a reliable environmental cue(s) that enables organisms to use current environmental information to induce the development of a phenotype with high fitness in a forthcoming environment. Here, we quantify predictability in the timing of precipitation and temperature change to examine how this is associated with seasonal polyphenism in tropical Mycalesina butterflies. Seasonal precipitation in the tropics typically results in distinct selective environments, the wet and dry seasons, and changes in temperature can be a major environmental cue. We sampled communities of Mycalesina butterflies from two seasonal locations and one aseasonal location. Quantifying environmental predictability using wavelet analysis and Colwell's indices confirmed a strong periodicity of precipitation over a 12-month period at both seasonal locations compared to the aseasonal one. However, temperature seasonality and periodicity differed between the two seasonal locations. We further show that: (a) most females from both seasonal locations synchronize their reproduction with the seasons by breeding in the wet season but arresting reproduction in the dry season. In contrast, all species breed throughout the year in the aseasonal location and (b) species from the seasonal locations, but not those from the aseasonal location, exhibited polyphenism in wing pattern traits (eyespot size). We conclude that seasonal precipitation and its predictability are primary factors shaping the evolution of polyphenism in Mycalesina butterflies, and populations or species secondarily evolve local adaptations for cue use that depend on the local variation in the environment.
  • Mobley, Kenyon B.; Granroth-Wilding, Hanna; Ellmen, Mikko; Orell, Panu; Erkinaro, Jaakko; Primmer, Craig R. (2020)
    Abstract In species with complex life cycles, life history theory predicts that fitness is affected by conditions encountered in previous life history stages. Here, we use a four-year pedigree to investigate if time spent in two distinct life history stages has sex-specific reproductive fitness consequences in anadromous Atlantic salmon (Salmo salar). We determined the amount of years spent in fresh water as juveniles (freshwater age, FW, measured in years), and years spent in the marine environment as adults (sea age, SW, measured in sea winters) on 264 sexually mature adults collected on a river spawning ground. We then estimated reproductive fitness as the number of offspring (reproductive success) and the number of mates (mating success) using genetic parentage analysis (>5000 offspring). Sea age is significantly and positively correlated with reproductive and mating success of both sexes whereby older and larger individuals gained the highest reproductive fitness benefits (females: 62.2% increase in offspring/SW and 34.8% increase in mate number/SW; males: 201.9% offspring/SW and 60.3% mates/SW). Younger freshwater age was significantly related to older sea age and thus increased reproductive fitness, but only among females (females: -33.9% offspring/FW and -32.4% mates/FW). This result implies that females can obtain higher reproductive fitness by transitioning to the marine environment earlier. In contrast, male mating and reproductive success was unaffected by freshwater age and more males returned at a younger age than females despite the reproductive fitness advantage of later sea age maturation. Our results show that the timing of transitions between juvenile and adult phases has a sex-specific consequence on female reproductive fitness, demonstrating a life-history trade-off between maturation and reproduction in wild Atlantic salmon.