Strong foraging preferences for Ribes alpinum (Saxifragales: Grossulariaceae) in the polyphagous caterpillars of Buff-tip moth Phalera bucephala (Lepidoptera: Notodontidae).

Juliano Morimoto,Zuzanna Pietras

doi:10.1002/ece3.6981

Abstract

Herbivorous insects such as butterflies and moths are essential to natural and agricultural systems due to pollination and pest outbreaks. However, our knowledge of butterflies' and moths' nutrition is fragmented and limited to few common, charismatic, or problematic species.This gap precludes our complete understanding of herbivorous insects' natural history, physiological and behavioral adaptations that drive how species interact with their environment, the consequences of habitat fragmentation and climate change to invertebrate biodiversity, and pest outbreak dynamics.Here, we first report a population of the Buff‐tip moth Phalera bucephala (Lepidoptera: Notodontidae) feeding on a previously unknown family of host plants, the mountain currant Ribes alpinum (Saxifragales: Grossulariaceae). This is the first report of a Notodontid moth feeding on Grossulariaceae hosts.Using no‐choice and choice assays, we showed that P. bucephala has strong foraging preferences for a previously unknown hosts, the R. alpinum but also, although to a smaller extent, R. uva‐crispa compared with a previously known host (the Norway maple Acer sp.).These findings demonstrate that P. bucephala feed on—and show strong preference for Grossulariaceae host plants, indicating flexible physiological mechanisms to accommodate hosts plants from various families. This makes this species a potential model organism to study the behavioral and physiological mechanisms underpinning insect–plant interactions and diet breadth evolution.We discuss the broad ecological implications of these observations to the biology of the species, the potential negative effects of interspecific competition with endemic specialist moths, and highlight questions for future research.

Highlights

Herbivorous insects display a wide variety of nutritional strategies in relation to diet, ranging from strict specialism to broad generalism (e.g., Lymantria dispar, D. suzukii) (Forister et al, 2015)
We described for the first time a previously unknown host plant for P. bucephala, a moth species that has been considered a transient pest in Europe and the UK
For the first time, P. bucephala feeding on Ribes. Such dietary flexibility to host plant families suggest that P. bucephala and possibly all Notodontids possess strong physiological robustness to cope with varying phytochemical defences

Summary

Introduction

Herbivorous insects display a wide variety of nutritional strategies in relation to diet, ranging from strict specialism (e.g., the Large Blue Phengaris arion, Drosophila seichellia) to broad generalism (e.g., Lymantria dispar, D. suzukii) (Forister et al, 2015). With the current recognition of the worldwide decline of insect species (Conrad et al, 2006; Didham et al, 2020; Saunders et al, 2020), specialists (i.e., “functional homogenisation”, Clavel et al, 2011), there is an unprecedented urgency for documenting suitable host plants of threatened species as well as species that can become/ are pests With this knowledge, it is possible to incorporate natural history into eco-evolutionary studies which will allow for informed decisions aimed to protect species in decline while mitigating negative effects of invasive or competitively superior species in a given ecosystem (Paine & Millar, 2002; Travis, 2020). Given that P. bucephala have been considered a transient pest in mainland Europe and the UK, our findings open questions in both applied and fundamental ecology

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