Home is where the heart rot is: Violet click beetle, Limoniscus violaceus (Müller, 1821), habitat attributes and volatiles

<p>The decreasing number of veteran trees in Europe threatens old-growth habitats and the fauna they support. This includes rare taxa, such as the violet click beetle, <i>Limoniscus violaceus</i> (Müller, 1821).</p> <p>Samples of wood mould were taken from all beech trees in Windsor Forest previously confirmed to have contained <i>L. violaceus</i> larvae, and from trees where <i>L. violaceus</i> had not previously been detected, the latter categorised as having high, medium or low likelihood of containing the beetle during recent surveys. Habitat characteristics were measured, and volatile profiles determined using gas-chromatography mass-spectrometry.</p> <p>Water content significantly differed between tree hollows of different<i> </i>violet click beetle status, high-potential habitats having higher and relatively stable water content compared with habitats with medium or low potential of beetle occupancy. Several volatile organic compounds (VOCs) were significantly associated with <i>L. violaceus</i> habitats. No differences in other characteristics were detected.</p> <p>The distinction in water regime between habitats highlights that recording this quantitatively could improve habitat surveys. Several potential <i>L. violaceus</i> attractant VOCs were identified. These could potentially be integrated into existing monitoring strategies, such as through volatile-baited emergence traps or volatile-based surveying of habitats, for more efficient population monitoring of the beetle.</p>