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 (June 11, 2018) - Pterostichus melanarius

This week's insect is the ground beetle, Pterostichus melanarius (Coleoptera: Carabidae).  This large (12-19 mm), shiny black beetle originates from Europe and probably arrived to North America in the 1920s in ships' ballasts. It has become a widespread insect throughout North America, particularly in habitats used by humans: urban areas, forests, and agricultural land.

Flight has been the main method of colonization and dispersal for this species. In newly arrived populations of P. melanarius, individuals generally have longer hind wings which allow for more efficient dispersal. After a population has become established in an area, short-winged morphs of the species become dominant.

This species is an excellent example of a generalist predator. Generalist predators include many species of ground beetles, some rove beetles, ants, centipedes and spiders. These arthropods are not picky when it comes to choosing a meal. For example, P. melanarius will eat nearly anything including many different arthropods, earthworms, slugs and even some small vertebrates. Generalist predators are effective in keeping some insects from reaching high numbers that can damage agricultural crops.

Find out more about ground beetles and Pterostichus melanarius at the Insect of the Week page!


Pterostichus melanarius
Photo credit: Henri Goulet (retired), Agriculture and Agri-Food Canada



Photograph of Pterostichus melanarius catching a fourth-instar P. xylostella in a plastic container (LRC, Photo credit: A. Mauduit)

Insect of the Week (21 May, 2018) - Ground beetles: cutworm natural enemies

 

This week's Insect of the Week is a large group of insects called ground beetles, also known as carabid beetles. Many species feed on cutworms as well as other pests.

Almost 400 different species of ground beetles occur on the Prairies, ranging in size from just a few millimetres to more than 2 centimetres. A field may contain 50 or more species, with densities ranging up to 10 beetles per square meter.

Ground beetles are characterized with long threadlike antennae, have a body that is flattened top-to-bottom, and have strong legs designed for running, large eyes, and obvious jaws (mandibles). Smaller ground beetle species can be important predators of cutworm eggs. Larger species attack and kill fully-grown cutworm larvae.

With all the work they do protecting your crop, ground beetles are real @FieldHeroes.

Find out more about ground beetles at the Insect of the Week page!



Adult Carabus nemoralis attacking a bertha armyworm caterpillar. 

Photocredit - Vincent Hervet, Agriculture and Agri-Food Canada

Species of ground beetles common in agricultural fields on the Prairies. 

From left to right: Bembidion quadrimaculatum, Agonum cupreum, 

Pterostichus melanarius, Calosoma calidum. 

Photocredit - Henri Goulet (retired), Agriculture and Agri-Food Canada

For a detailed review of ground beetle research, biology, distribution, habitat, diet, etc., see Chapter 1: Ground Beetles (Coleoptera: Carabidae) of the Prairie Grasslands of Canada.

**NEW - Don't forget there's a new cutworm identification manual you can download from the Cutworm Field Guide page - NEW**

Insect of the Week (May 30, 2016) - Ground beetles

Ground beetles (predator)

Last year, the focus of the Insect of the Week was crop pests. This year, we’re changing things up and highlighting the many natural enemies that help you out, silently and efficiently killing off crop pests. [note: featured Insects of the Week in 2015 are available on the Insect of the Week page] 

This week’s Insect of the Week is the ground beetle. There are nearly 400 known ground beetle species on the prairies. Some of these provide important pest control service: eating redbacked cutworm eggs, grasshopper eggs, pea leaf weevil eggs, cabbage maggots and diamondback moth larvae. See more information in the new Field Crop and Forage Pests and their Natural Enemies in Western Canada - Identification and Management Field Guide for identification, life cycle and conservation options (download links for field guide available on the Insect of the Week page).

The ground beetle Pterostichus melanarius can help prevent pest outbreaks of diamondback moth (Plutella xylostella). © Canadian Biodiversity Information Facility (www.cbif.gc.ca)

For those that just can’t get enough about the fascinating world of insects, Ground Beetles (Coleoptera: Carabidae) of the Prairie Grasslands of Canada is a recent literature review on the topic.