There is far more to wasps and hornets than you might expect.
This group of insects is massive and it contains many beneficial insects. You may not be familiar with chalcidoid wasps, but odds are pretty high they’ve been working hard in your garden all along.
The chalcidoid superfamily of wasps contains 22,500 known species, with an estimated 500,000 species yet to be named. One of those families in particular, the Chalcididae, gives us chalcid wasps. And figs.
Chalcid wasp description
Ranging from only 1.5 to 0.75 mm (1/50 - 1/100”), you could fit 12 to 24 chalcid wasps nose-to-tail across a dime, so you probably will never see one. If you could see them, you would understand how they got their name. The word ‘chalcid’ comes to us from the Greek word for ‘copper’ because most chalcid wasps are a metallic bronze or copper color, though some species are metallic blue or green, and some are the more classic black and yellow variety.
Beneficial chalcid wasps
Most chalcids are parasitic wasps. They lay their eggs in several common garden pests. When the eggs hatch, larvae feed on the host insect before pupating into adult wasps. [I know, it’s sounds awful.] Those hosts include the eggs and larvae of flies, beetles, moths and butterflies, some spiders and nematodes, and true bugs. Since true bugs (Hemiptera) include aphids, leafhoppers, spittlebugs, thrips, whiteflies, and scale insects, I am all for more chalcid wasps! [Plus, I love figs!]
Figs and tiny wasps
While most chalcidoid wasps parasitize all those pests, a handful of them are phytophagous, which means the larvae hide and feed in stems, galls, seeds, and flowers. Fig flowers, in particular, are hidden clusters found inside a hollow structure called a syconium. Fig pollination is usually completed by tiny specialized wasps, such as chalcid wasps.
But, not all chalcids are good.
Chalcids as pests
Other phytophagous chalcids are not so helpful. These tiny wasps are pests because they lay their eggs in seeds. When those eggs hatch, larvae eat the seeds of pistachios and alfalfa, among others, creating burrows and allowing fungal and bacterial diseases a point of entry.
In many cases, sticky barriers can be used to reduce the damage caused by these pests. Most chalcids, however, are beneficial.
You can attract chalcid wasps to your garden by installing insectary plants, such as yarrow.
You can grow a surprising amount of food in your own yard. Ask me how!