Spring threshing surprise - Seeking beetle data please!

Reminder - Large numbers of adult Amara ground beetles are being reported this spring (Fig. 1) in canola fields left unharvested last fall. These are non-pest beetles.  Adults feed on seeds, particularly those of cruciferous plants.  Larvae eat pest insects (e.g., grasshopper eggs).

Figure 1. An aggregation of Amara littoralis near Pickardville, AB. This was one of several outbreaks of
carabids observed in central Alberta in the autumn of 2010.  Photo B. Berry.

Read the full post and find a request for beetles posted in Wk03!

Spring threshing surprise - Seeking beetle data please!

Large numbers of adult Amara ground beetles are being reported this spring (Fig. 1) in canola fields left unharvested last fall. These are non-pest beetles.  Adults feed on seeds, particularly those of cruciferous plants.  Larvae eat pest insects (e.g., grasshopper eggs).

Figure 1. An aggregation of Amara littoralis near Pickardville, AB. This was one of several outbreaks of
carabids observed in central Alberta in the autumn of 2010.  Photo B. Berry.

View another image of this beetle species at Bug Guide.  More images and life history information is available online at the Royal Alberta Museum or read this published Scientific Note by Floate and Spence (2015) describing previous reports of this species.

High numbers of these beetles may be due to an abundance of canola seed left on the ground last fall, which would have provided an ample food supply for adults going in the winter.  These overwintered adults have now emerged and are active.  They will lay their eggs in the soil during the next few weeks with their adult progeny emerging in late summer, which may generate more reports of their high abundance.

Dr. Kevin Floate (AAFC-Lethbridge) is interested in studying this phenomenon. If you observe an ‘outbreak’ of ground beetles, Dr. Floate is looking for the following information:
1. General location
2. 30 to 50 adult beetles collected from the ‘outbreak’ for identification (these can be stored in a small jar of rubbing alcohol)
3. Cropping history of the field where the ‘outbreak’ was observed, going back at least 2 years
4. The scope of the ‘outbreak’ (i.e. the number of acres affected), and
5. An estimate of beetle density (e.g., best guess of number of beetles per m2 or high resolution pictures of the outbreak)

Please contact Dr. Floate directly (kevin.floate@canada.ca) if you have observed a ground beetle ‘outbreak’ and are able to share information.

Thank you!

Insect of the Week (August 20, 2018) - Biological control agents of weeds

As we are nearing the end of the 2018 growing season, we decided to feature something a little bit different for this week’s Insect of the Week: insects that are biological control agents of weeds. Natural enemies of insects include parasitoids and predators that kill insect pests. Natural enemies of weeds include plant pathogens or insect herbivores that impact weed growth and reproduction, thus reducing reduce weed density. There are many insects that may be found in rangeland, forage and crop habitats that are biological control agents of weeds, some of which have been introduced purposely after rigorous testing for safety from places where our invasive plants have originated. Biological control agents of weeds act in two primary ways: plant herbivory and granivory. Plant herbivores consume root, leaves and./or shoots enough to typically reduce its ability to grow and reproduce, and thus its ability to compete with rangeland plants used in cattle grazing or with crops. Granivores or weed seed predators consume high numbers of weed seeds, thus reducing the number of viable weed seeds entering seed banks for germination in future growing seasons.

Ground beetles (Coleoptera: Carabidae) of several genera are known to eat weed seeds within crops, including Harpalus, Amara, Poecilus, and Pterostichus. The diets of some ground beetles almost entirely consist of weed seeds. Other ground beetles are primarily carnivores (i.e., generalist predators of other insects or slugs) that occasionally consume weed seeds. More information about the biology of ground beetles can be found by visiting the Insect of the Week page.

Mogulones crucifer (Pallas) is a biological control agent of hound's-tongue (Cynoglossum officinale L.), a weedy pest of rangelands in southern British Columbia and southwestern Alberta. The adult stage of this weevil species (Coleoptera: Curculionidae) feeds on leaves of its host while the larvae consume the roots of the host plant. The weevil is highly mobile and has significantly reduced hound's-tongue densities where it has been released for biological control. For more information about M. crucifer, visit https://www.for.gov.bc.ca/hra/plants/biocontrol/detailed_bioagent_pages/Mogulones_cruciger.htm

Prepared by Dr. Meghan Vankosky

Hound’s-tongue, an invasive species, is a host plant for Mogulones crucifer
Photo: Jacob W. Frank

Mogulones crucifer adult on hound's-tongue leaf

photo: Rosemarie De Clerk-Floate

Mogulones crucifer larvae infesting hound's-tongue root

photo: Rosemarie De Clerk-Floate