DOI: 10.5061/dryad.5qfttdzdp
title: Data from: Oviposition strategies of Pieridae butterflies in nature and the role of an egg-killing plant trait therein

description: Most herbivorous insects are host-plant specialists that evolved
 detoxification mechanisms to overcome their host plant’s toxins. In the
 evolutionary arms-races between Pieridae butterflies and Brassicaceae
 plants, some plant species have evolved another defence against the
 pierids: egg-killing. Underneath the eggs, leaves develop a so-called
 hypersensitive response HR-like cell death. Whether some butterflies have
 evolved oviposition strategies to counter-adapt against egg-killing
 remains to be studied. In this study, we assessed the oviposition site
 location of pierid butterflies on their natural host plants. We described
 the plant tissue on which we located the eggs of the most common Pieridae
 in the Netherlands: Gonepteryx rhamni, Anthocharis cardamines, Pieris
 rapae, P. napi, P. brassicae, and P. mannii. Additionally, we assessed
 expression of HR-like cell death in response to the deposited butterfly
 eggs. We found that both A. cardamines and G. rhamni mainly oviposited on
 the floral stem and the branch, respectively, and oviposited on host
 plants from lineages not expected to express HR in response to pierid
 eggs. Accordingly, no HR responses were seen. All Pieris eggs found were
 located on leaves of their host, the only tissue found to express HR-like
 cell death. Furthermore, each Pieris species was found to at least
 occasionally oviposit on Brassica nigra. This was the only plant species
 in this survey that expressed HR-like cell death in response to the eggs
 of P. rapae, P. napi and P. brassicae. Our observations demonstrate that
 HR-like cell death remains an effective defence strategy against these
 Pieris species and as such did not find evidence for the hypothesised
 counterstrategies. Surveying certain key species and disentangling the
 micro-evolution of oviposition strategies within a species would allow us
 to further  investigate potential counter-adaptations that
 evolved against HR-like cell death. This study provides the basis for
 further investigation of potential counter-adaptations to egg-killing
 defences.
description: Fieldwork for this research was conducted in the provinces
 Gelderland and South Limburg in the Netherlands between April and July
 2021. Eggs of <em>G. rhamni</em> were found at five locations
 in Renswoude, Wageningen and Wijchen. These locations were near roads and
 in forests. Eggs of <em>A. cardamines </em>were found at 12
 locations in Wageningen, Wijchen, Arnhem and Vijlen (South Limburg). All
 locations were near streams or along paths. All <em>Pieris
 </em>eggs were found along paths, in fields, and gardens at 16
 locations in Wageningen and Wijchen. All host plants were checked as they
 were found in the search locations. Therefore, some host plants were found
 more often than others. For all herbaceous plants, all parts of the plants
 were checked for eggs. For egg searching on <em>Rhamnus
 frangula</em> all leaves and twigs on branches within a height of ±
 2 m to the ground were checked for eggs.The position of each egg was
 recorded by the following categories: branch, leaf, flower bud.
 Additionally, the presence of HR-like cell death was carefully observed
 with a magnifier or camera with a macro lens.
description: # Oviposition strategies of Pieridae butterflies in nature and the role of
 an egg-killing plant trait therein
 This dataset contains all
 eggs found during fieldwork in the provinces Gelderland and South Limburg
 in the Netherlands between April and July 2021. Common Pieridae butterfly
 species in the Netherlands were screened, namely *G. rhamni, A.
 cardamines, P. rapae, P. napi, P. brassicae,* and *P. mannii*. For each
 egg we recorded host plant, egg position on the plant, presence of HR-like
 cell death underneith the egg, and location of the plant. ## Description
 of the data and file structure This dataset contains seven rows: Data
 point, species, HR-like cell death, plant species, location, and date.
 Data point - each data point is a single egg. Species - Butterfly species
 name (*P. rapae*, *P. napi*, and *P. mannii* are grouped under Solitary
 Pieris) HR-like cell death - Cell death was scored with its severity
 scored from 1 to 3 and 0 meaning no cell death. Plant species - the plant
 species the egg was found on. Location - location where the plant with egg
 was found. Date - date on which the egg was found. n.a. - not available.