Gall Wasps

Cynipidae

Classification

Pronunciation

How to pronounce Cynipidae: /sɪˈnɪpɪˌdiː/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Images

Andricus topiarius by the Smithsonian. Used under a CC0 license.
Xystoteras volutellae by the Smithsonian. Used under a CC0 license.
Diastrophus fragariae by the Smithsonian. Used under a CC0 license.
Andricus topiarius by the Smithsonian. Used under a CC0 license.
Xystoteras volutellae by the Smithsonian. Used under a CC0 license.
Andricus texanus by the Smithsonian. Used under a CC0 license.

Summary

Cynipidae, known as gall wasps, are small hymenopterans that induce galls on various plants, especially oak. They reproduce through a mix of sexual and parthenogenetic means and have significant ecological and historical importance due to their interactions with host plants and usage in human culture.

Physical Characteristics

Body shape with a distinctive wasp waist; hind tarsi first segment about as long as the following two or three combined; most species are humpbacked; abdomen with two segments visible dorsally and the remainder telescoped beneath; size ranges from 2 to 8 mm.

Identification Tips

Observation of the galls produced is usually more effective for species determination than the insect itself. Galls vary widely in appearance and location on host plants.

Habitat

Gall wasps primarily inhabit various oak species, but some also live in eucalyptus, maple, and many herbs. Galls can be found on leaves, buds, branches, and roots.

Distribution

Globally, over 1,300 species are known, with about 360 species found in Europe and around 800 in North America.

Diet

Larvae feed on nutritive tissue within the galls they induce, usually on oak trees, which encompass about 70% of known species.

Life Cycle

Gall wasps usually have an alternating generation cycle, with one sexual generation and one parthenogenic generation annually. The larvae develop in galls, and some species may overwinter inside galls for extended periods.

Reproduction

Reproduction often involves both parthenogenesis and sexual reproduction. Some species reproduce exclusively via parthenogenesis due to infections by endosymbiotic Wolbachia bacteria, producing predominantly agamic females.

Predators

Gall wasps are preyed upon by hyperparasitoids and other insects that target the larvae within the galls.

Ecosystem Role

Gall wasps play a significant role in their ecosystems by inducing galls on plants, which fosters biodiversity and provides habitat for other organisms.

Economic Impact

Historically, galls, especially from Mediterranean variants, were used in tanning and for making iron gall ink, which was prominent in ancient and medieval writing.

Cultural Significance

Galls formed on oak trees were used in the creation of iron gall ink, a significant medium for writing in history. Alfred Kinsey studied gall wasps before his research in human sexuality.

Collecting Methods

  • Collecting galls from host plants
  • Observing gall formations on multiple trees

Preservation Methods

  • Drying specimens
  • Embedding in resin

Evolution

The Cynipidae family shows a complex evolutionary history reflected in phylogenetic studies, including both internal and external phylogenetic analyses.

Similar Taxa

Misconceptions

Gall wasps do not significantly harm oak trees; the galls may appear detrimental, but they are part of a natural process.

Tags

  • Gall Wasps
  • Cynipidae
  • Insect
  • Hymenoptera
  • Gall Induction