Pollen chemical and mechanical defences restrict host-plant use by bees
Data files
Feb 27, 2024 version files 40.11 KB
Abstract
Plants produce an array of chemical and mechanical defences that provide protection against many herbivores and pathogens. Putatively defensive compounds and structures can even occur in floral rewards: for example, the pollen of some plant taxa contains toxic compounds or possesses conspicuous spines. Yet little is known about whether pollen defences restrict host-plant use by bees. In other words, do bees, like other insect herbivores, tolerate the defences of their specific host-plants while being harmed by non-host defences? To answer this question, we compared the effects of a chemical defence from Lupinus (Fabaceae) pollen and a putative mechanical defence (pollen spines) from Asteraceae pollen on larval survival of nine bee species in the tribe Osmiini (Megachilidae) varying in their pollen host use. We found that both types of pollen defences reduce larval survival rate in some bee species. These detrimental effects were, however, mediated by host-plant associations, with bees being more tolerant of the pollen defences of their hosts, relative to the defences of plant taxa exploited by other species. This pattern strongly suggests that bees are adapted to the pollen defences of their hosts, and that host-plant use by bees is constrained by their ability to tolerate such defences.
README: Pollen chemical and mechanical defences restrict host-plant use by bees
https://doi.org/10.5061/dryad.h44j0zpsx
Data and code to analyse the survival rate of Osmiini larvae exposed or not to Asteraceae spines or Lupinus alkaloids in their pollen and nectar provisions.
Description of the data and file structure
Osmiini_survival_data
This dataset countains data on the survival of Osmiini larvae exposed or not to Asteraceae spines or Lupinus alkaloids in their pollen and nectar provisions.
- Year: year of nest collection (2021 or 2022).
- ID: unique identifier for each larva monitored in a given year.
- Species: species name of the larva monitored.
- Stage: whether the monitored larva was introduced to its provision at the larval or egg stage.
- Diet: pollen-host use type of the larva monitored (generalist, Asteraceae specialist, Fabaceae specialist, or cleptoparasite).
- Experiment: sub-experiment to which the larva was assigned (Asteraceae pollen spines: aster or Lupinus alkaloids: lup).
- Treatment: whether the larva was a control (C) or a treatment (T).
- Site: site from which the nest was collected.
- Bloc: identifier of the artificial nesting structure from which the nest was collected.
- Nest: identifier of the hole within a given artificial nesting structure from which the nest was collected. Only one nest was present in each hole. The letter "x" was given to nests for which information on their position within the bloc was missing.
- Cell: identifier of the cell (each containing one egg and a pollen and nectar provision) within a given nest.
- Date.transferred: date at which the provision was manipulated and the egg was put on the manipulated provision. This corresponds to the start of larval monitoring. The number indicates the day of the month, and the letters correspond to the month in roman numerals.
- days.to.event: number of days before the larva either died or started spinning its cocoon.
- status: whether the larvae either died (2) or reached the cocoon spinning stage (1).
Code/Software
osmiini_survival
R code for the analysis of Osmiini survival data. The code contains models of the effect of Asteraceae pollen spines and Lupinus pollen alkaloids on the survival probability of 9 species of bees in the Osmiini tribe and their cleptoparasite (sapyga. sp).