title: Female fecundity variation affects reproducibility of experiments on host plant preference and acceptance in a phytophagous insect.
abstract: Reproducibility is a scientific cornerstone. Many recent studies, however, describe a reproducibility crisis and call for assessments of reproducibility across scientific domains. Here, we explore the reproducibility of a classic ecological experiment-that of assessing female host plant preference and acceptance in phytophagous insects, a group in which host specialization is a key driver of diversification. We exposed multiple cohorts ofPieris napibutterflies from the same population to traditional host acceptance and preference tests on three Brassicaceae host species. Whereas the host plant rank order was highly reproducible, the propensity to oviposit on low-ranked hosts varied significantly even among cohorts exposed to similar conditions. Much variation could be attributed to among-cohort variation in female fecundity, a trait strongly correlated both to female size and to the size of the nuptial gift a female receives during mating. Small males provide small spermatophores, and in our experiment small females that mated with small males had a disproportionally low propensity to oviposit on low-ranked hosts. Hence, our results provide empirical support to the theoretical prediction that female host utilization is strongly affected by non-genetic, environmental variation, and that such variation can affect the reproducibility of ecological experiments even under seemingly identical conditions.
authors.affiliation: Department of Zoology, Stockholm University, 10691, Stockholm, Sweden.
authors.forename: Alexander
authors.initials: A
authors.lastname: Schäpers
authors.affiliation: Department of Plant Ecology and Evolution, Evolutionary Biology Centre, EBC, Uppsala University, Norbyvägen 18D, 752 36 Uppsala, Sweden.
authors.forename: Hampus
authors.initials: H
authors.lastname: Petrén
authors.affiliation: Department of Zoology, Stockholm University, 10691, Stockholm, Sweden.
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Wheat
authors.affiliation: Department of Zoology, Stockholm University, 10691, Stockholm, Sweden.
authors.forename: Christer
authors.initials: C
authors.lastname: Wiklund
authors.affiliation: Department of Plant Ecology and Evolution, Evolutionary Biology Centre, EBC, Uppsala University, Norbyvägen 18D, 752 36 Uppsala, Sweden magne.friberg@ebc.uu.se.
authors.forename: Magne
authors.identifier: 0000-0003-4779-7881
authors.initials: M
authors.lastname: Friberg
mesh_terms: D000818:Animals; D019607:Brassicaceae; D002080:Butterflies / Q000502:physiology*; D005260:Female; D005298:Fertility; D008297:Male; D010058:Oviposition; D015203:Reproducibility of Results
keywords: effect-sample size; fecundity; host plant preference; nuptial gift; quasi-replication; reproducibility