Trigonalidae
Encyclopedia
Trigonalidae is one of the more unusual families of hymenoptera
n insect
s, of indeterminate affinity within the suborder Apocrita
(though sometimes believed to be related to the Evanioidea
), and presently placed in its own superfamily, Trigonaloidea. Trigonalidae is divided into two subfamilies, Orthogonalinae and Trigonalinae. These wasps are extremely rare but surprisingly diverse, with some 90 species in over 15 genera, and are known from all parts of the world.
What little is known about the biology
of these insects indicates a remarkably improbable life history: in nearly all known species, females lay thousands of minute eggs, "clamping" them to the edges or injecting them inside of leaves. The egg must then be consumed by a caterpillar
. Once inside the caterpillar, the trigonalid egg either hatches and attacks any other parasitoid
larvae (including its siblings) in the caterpillar, or it waits until the caterpillar is killed and fed to a vespid
larva, which it then attacks. Therefore, they are parasitoid
s or hyperparasitoids, but in a manner virtually unique among the insects, in that the eggs must be swallowed by a host. A few species are known to directly parasitise sawflies, however.
Hymenoptera
Hymenoptera is one of the largest orders of insects, comprising the sawflies, wasps, bees and ants. There are over 130,000 recognized species, with many more remaining to be described. The name refers to the heavy wings of the insects, and is derived from the Ancient Greek ὑμήν : membrane and...
n insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...
s, of indeterminate affinity within the suborder Apocrita
Apocrita
Apocrita is a suborder of insects in the order Hymenoptera.Apocrita includes wasps, bees and ants, and consists of many families. It includes the most advanced hymenopterans and is distinguished from Symphyta by the narrow "waist" formed between the first two segments of the actual abdomen; the...
(though sometimes believed to be related to the Evanioidea
Evanioidea
Evanioidea is a small Hymenopteran superfamily that includes three families, two of which are much more closely related to one another than they are to the remaining family, Evaniidae. There is a rich fossil record, however, that helps fill in the gaps between these lineages...
), and presently placed in its own superfamily, Trigonaloidea. Trigonalidae is divided into two subfamilies, Orthogonalinae and Trigonalinae. These wasps are extremely rare but surprisingly diverse, with some 90 species in over 15 genera, and are known from all parts of the world.
What little is known about the biology
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...
of these insects indicates a remarkably improbable life history: in nearly all known species, females lay thousands of minute eggs, "clamping" them to the edges or injecting them inside of leaves. The egg must then be consumed by a caterpillar
Caterpillar
Caterpillars are the larval form of members of the order Lepidoptera . They are mostly herbivorous in food habit, although some species are insectivorous. Caterpillars are voracious feeders and many of them are considered to be pests in agriculture...
. Once inside the caterpillar, the trigonalid egg either hatches and attacks any other parasitoid
Parasitoid
A parasitoid is an organism that spends a significant portion of its life history attached to or within a single host organism in a relationship that is in essence parasitic; unlike a true parasite, however, it ultimately sterilises or kills, and sometimes consumes, the host...
larvae (including its siblings) in the caterpillar, or it waits until the caterpillar is killed and fed to a vespid
Vespid
The Vespidae are a large , diverse, cosmopolitan family of wasps, including nearly all the known eusocial wasps and many solitary wasps. Each social wasp colony includes a queen and a number of female workers with varying degrees of sterility relative to the queen. In temperate social species,...
larva, which it then attacks. Therefore, they are parasitoid
Parasitoid
A parasitoid is an organism that spends a significant portion of its life history attached to or within a single host organism in a relationship that is in essence parasitic; unlike a true parasite, however, it ultimately sterilises or kills, and sometimes consumes, the host...
s or hyperparasitoids, but in a manner virtually unique among the insects, in that the eggs must be swallowed by a host. A few species are known to directly parasitise sawflies, however.