Yellow Mealworm beetle
The yellow mealworm beetle (Tenebrio molitor) is quite a large insect up to 15mm long with even longer larvae, which are commonly for sale as pet and bird food. They are widespread throughout the UK, but are usually not present in large numbers and not considered a storage pest. They are associated with birds nests, spilled flour, food and other debris. They are omnivorous and readily scavenge on carrion. It takes a year for larvae to grow into an adult. Their presence can be indicative of a neglect of hygiene if they are present in significant numbers. Alternatively the the presence of a hidden birds nest or an animal carcass hidden from view might be a breeding source. Other member of the Mealworm beetle family (Tenebrio sp.) include the Dark mealworm beetle (Tenebrio obscurus).
Mealworm beetles and their larvae can occasionally be present in any setting and enter homes irrespective of hygiene standards. However, large numbers are indicative of a hidden food source or poor hygiene standards. Residual insecticides can reduce an infestation, but removing the food source should be a priority for effective control.
The larder beetle (Dermestes lardarius) is about 8mm long with a distinct beige band across the front of the elytra. Larvae are about 12 mm in length and hairy. Larder beetle larvae feed on animal protein including hides, meat, feathers and bone meal. They are often encountered as secondary infestations originating from birds nests.
An infestation of Larder beetles is sometimes a sign of poor hygiene, as they eat scattered food scraps (high in protein and fat). Their requirement for tunneling before they pupate and damage to structural materials (wood, polystyrene etc.) is also a cause for concern.
The best control method is removal of food availability and an improvement of hygiene. A possible source of the infestation might be birds nests in chimneys and voids, as decaying animals and feathers provide an ideal breeding site. Treatment with a residual insecticide to curtail an infestation is the second most appropriate cause of action.
We cover the following districts
WI: Wigan and Leigh, WL: West Lancashire, CL: Chorley, PR: Preston, BL: Bolton, HE: St. Helens, MA: Manchester, WA: Warrington, KN: Knowsley, LP: Liverpool, SE: Sefton, SP: Southport, HT: Halton, SA: Salford; TR: Trafford, SK: Stockport, TS Tameside, BR: Bury, RD: Rochdale, BB, Blackburn, HB: Hyndburn, Fl: Fleetwood, WR: Wirral, CW, CC, CE: Cheshire west, central and east.