Spring dispersal and reproductive potential Ips typographus

Diapause is a common strategy in insects to respond to reoccurring adverse events. The European spruce bark beetle Ips typographus is an important forest pest in Eurasia affecting spruce-dominated forests by eruptive outbreaks, which are likely to become more frequent and severe in a changing climate. It expresses a reproductive diapause to cope with harsh winter conditions. As diapause also affects the activity and voltinism of I. typographus, understanding its regulation by abiotic environmental factors can help to mitigate outbreak risks, e.g. by coordinating management measures or adapting silvicultural strategies. While diapause induction in late summer and autumn has been shown to be mainly triggered by photoperiod and modified by temperature, information on environmental cues affecting post-diapause swarming in spring is scarce. In late winter/early spring 2021 and 2023, we conducted a laboratory experiment assessing spring swarming and reproductive potential of I. typographus af..., In laboratory experiments performed in 2021 and 2023, emergence of Ips typographus von experimental logs and the reprodutive potential of female beetles was assessed under different controlled fluctuating temperatures and daylengths., , # Spring dispersal and reproductive potential Ips typographus

[https://doi.org/10.5061/dryad.0k6djhb9b](https://doi.org/10.5061/dryad.0k6djhb9b)

## Description of the data and file structure

In late winter/early spring 2021 and 2023, we conducted a laboratory experiment assessing spring swarming and reproductive potential of *I. typographus* after diapause termination under various temperature and photoperiodic conditions. We applied mean temperatures between 13 and 23 °C with daily oscillations of ±5 °C and daylengths between 9 and 14 h (January to April). Flight activity was assessed by counting emerging beetles from experimental logs, while reproductive potential was assessed by disecting female beetles to record the mean number of eggs per ovariole and the mean relative vitellarium length.

### Files and variables

#### File: data21.csv

**Description:** all data recorded in the experiment in 2021

##### Variables

* trial: trial of the respective observation
* start: start of th...