Predatory rove beetle

Dalotia coriaria
(formerly Atheta coriaria)

Adults of Dalotia coriaria are small, slender rove beetles, dark brown to black in Colour and approximately 3—4 mm long. Both adults and larvae are generalist predators of soil-dwelling pests, including the immature stages of fungus gnats (Family Sciaridae) and shore flies Family Ephydridae), as well as thrips pupae. As in other beetles, the hind wings are folded under the modified forewings (elytra) when not in use, but in rove beetles, the very short elytra leave most of the abdomen exposed. This allows rove beetles to curve their abdomen upwards when disturbed, a behaviour characteristic of this family.

Dalotia coriaria adults fly actively (mainly at night) and can disperse readily. Nevertheless, the adults are usually found in or on the growing medium, adapting well to a variety of substrates (including peat mixes and coir). There are three larval stages, the first of which is whitish in colour; subsequent instars are somewhat darker, with the last Iarval stage being yellowish/pale tan. When monitoring, gently disturbing the top 1-2 cm of soil can reveal their presence: all of the larval stages move rapidly and readily enter cracks and crevices in the soil. Pupation also occurs in the growing medium.

Optimum temperatures for this species lie between 20 and 25°C (68—77°F); at 21°C (70°F),  the life-cycle takes approximately 18 days. High temperatures (approaching 32°C/90°F) may reduce the survival of immature stages. Estimates of adult longevity vary from approximately 3 to 8 Weeks, depending on environmental conditions. This species does not seem to enter diapause under most greenhouse conditions.