Evidence of reproduction in the wild demonstrates initial success for reintroducing a critically endangered saproxylic hoverfly to a Scottish forest ecosystem

Saproxylic insects play a crucial role in forest ecosystems and serve as indicators of forest health. Such species are sensitive to commercial forestry management and have been historically overlooked by conservation. Insects in general are underrepresented in conservation translocation programs, but this is especially true for saproxylic insects, among which saproxylic Diptera are particularly neglected, despite being as speciose as better-studied orders like Coleoptera. Here, we report on the first five years of a large-scale conservation breeding and reintroduction effort for a saproxylic syrphid, the pine hoverfly (Blera fallax), which, in the UK, was restricted to just one site in Scotland and is classed as UK Critically Endangered. Starting with 25 founders collected from the remnant UK population, our zoo-based conservation breeding programme has produced ~8,000 pine hoverfly larvae per year for three years. This, combined with extensive habitat management at reintroduc..., , # Evidence of reproduction in the wild demonstrates initial success for reintroducing a critically endangered saproxylic hoverfly to a Scottish forest ecosystem

Dataset DOI: [10.5061/dryad.tht76hf9s](10.5061/dryad.tht76hf9s)

## Description of the data and file structure

We collected data from our ex-situ breeding programme for pine hoverfly (*Blera fallax*) on dates of pupation, dates of adult emergence, sex, and adult lifespans in the adult flight season in 2021, 2022, and 2023 at RZSS Highland Wildlife Park, Scotland. We also present data from pine hoverfly larval surveys at three release sites for animals from the breeding programme in the Strathspey area of the Cairngorms National Park. All missing data represented as NA.

### Files and variables

#### File: AFD_2021.csv

**Description:** 

This file contains the raw data from 2021 to reproduce the analyses on the ex-situ breeding population at Highland Wildlife Park

Variables in this file are coded as follows

* Year laid: The ...,