Collecting Stephanids

Blue Pan Traps

Blue pans used by Aguiar & Sharkov (1997)

This is the method I believe is the most promising for collecting stephanid wasps. I had the opportunity to try out the idea in a collection trip to St. Catherines Island (Georgia, USA), together with Andrey Sharkov. We set 155 yellow pan traps and 39 blue ones, at ground level, with water/detergent as collecting medium. We collected 7 female Megischus bicolor along three days, all of them in the blue pan traps only (Aguiar & Sharkov 1997)*.

Shaded areas at the edge of an oak-pine forest, at St. Catherines Island, where Megischus bicolor specimens were collected in blue pan traps. Note the presence of fallen/dead branches.

The fact that all stephanids were collected only in blue traps, ignoring a much higher number of closeby yellow ones, strongly suggests a preference of that color to yellow. Kirk (1984) also observed that white or blue pan traps work as well as, or better than yellow in attracting insect predators and parasitoids not associated with foliage.

To say that "only" seven specimens were collected is to underestimate the results. Stephanids are usually rare, and most museums have no specimens at all, in spite the fact the group is distributed worldwide. Additionally, no one had ever before collected stephanids on St. Catherines Island, in spite of years of collecting efforts by many entomologists who worked there (inclunding A. Sharkov!)

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* One more female was collected on August/99, also in a blue pan trap!

Malaise Traps

Malaise traps seem to be of very limited use in collecting stephanids. I tested Malaise traps (Townes model) in an area near Manaus (Brazil AM), with a large population of stephanids, for five consecutive days, but none were captured by this trap. During the same period, however, I was able to collect about 70 stephanids with a hand-net. Similarly, most of the stephanids at INBIO were collected with a hand net, and Hanson & Gauld (1995) only collected a dozen or so stephanids, in spite of a massive collecting effort with Malaise traps by these individuals/institution. Finally, only a tiny fraction of 3000 stephanids I have seen so far (from about 100 museums worldwide) was collected with Malaise.

Stephanid Size and Malaise Trapping Success

The stephanids collected in Malaise traps, however, seem to be the large ones, as for example the North American Schlettererius cinctipes, and the usually gigantic Megischus furcatus and M. maculipennis, from South America. Larger stephanids may have a more powerful and/or active flight, and thus would be more prone to be captured in Malaise traps. This idea agrees with observations of a very agile flight for the large S. cinctipes, and the contrastingly slow, easy-to-follow flight pattern of most Hemistephanus species I observed in Manaus, which were of medium to small size, and never collected in my Malaise traps.

References

Aguiar, A. P. & A. Sharkov. 1997. Blue pan traps as a potential method for collecting Stephanidae (Hymenoptera). Journal of Hymenoptera Research, 6(2): 422-3.

Kirk, W. D. J. 1984. Ecologically selective coloured traps. Ecological Entomology 9:35-41.

This page last updated: August 19, 1998.