Insect of the Week (Aug 6) - Doppelgangers – good vs. good (ladybeetle larva vs. lacewing larva)

Often life choices involve lesser evils. But in the case of lady beetle larva and lacewing larva, they both contribute to the greater good. But which one do you have? Both are voracious aphid, mite, mealy bug, insect egg and other soft bodied insect hunters. In fact, lady beetle larva can consume hundreds of aphids during their development. Lacewing larva are no slouch in that department either. Another name for them is aphidlion and they can consume up to 200 aphids per week.

Green lacewing larva
cc by 3.0 Whitney Cranshaw

Ladybird beetle larva
cc by 3.0 Frank Peairs

While both have the same general tapered alligator body, there are few main characteristics that will help to tell them apart.

For more information about these species and more tips on telling them apart, see our Insect of the Week page).

The case of the innocuous versus the evil twin: When making pest management decisions, be sure that the suspect is actually a pest. This can be challenge since insects often mimic each other or look very similar. An insect that looks, moves and acts like a pest may in fact be a look-alike or doppelganger.

Doppelgangers may be related (e.g. same genus) or may not be related, as in the case of monarch butterflies (Danaus plexippus) and viceroys (Limenitis achrippus).  Doppelgangers are usually relatively harmless but sometimes the doppelganger is a pest yet their behaviour, lifecycle or hosts may be different.

Correctly identifying a pest enables selection of the most accurate scouting or monitoring protocol. Identification and monitoring enables the application of economic thresholds. It also enables a producer to select and apply the most effective control option(s) including method and timing of application.  For the rest of the growing season, the Insect of the Week will feature insect crop pests and their doppelgangers.

Review previously featured insects by visiting the Insect of the Week page.