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HYMENOPTERA, Chrysididae (Dahlbom 1854) (Chrysidoidea) -- <Images> & <Juveniles> (Bethyloidea). Please refer also to the following
link for details on this group: Description & Statistics
Chrysididae.-- Cuckoo wasps are small insects,
rarely over 11 mm long. Their color
is metallic green or blue, and usually the body is coarsely sculptured. They resemble some of the chalcids and
bees in size and coloration, but a more complete venation in the front wing
but no closed cells in the hind wing distinguish the cuckoo wasps. Also the structure of the abdomen is
distinctive and has only 3-4 visible segments and is hollowed ventrally. When
a cuckoo wasp is disturbed, it usually curls up in a ball. Most species are
external parasitoids of full-grown wasp or bee larvae; the species in the
genus Cleptes attack sawfly larvae, and those in Mesitiopterus attack
the eggs of walking sticks (Borror et al., 1989). The family Chrysididae
is a very large cosmopolitan group (over 3010 described species) of
parasitoid or cleptoparasitic wasps, often highly sculptured, with
brilliantly colored metallic-like bodies (thus the common names jewel wasp,
gold wasp, or emerald wasp are sometimes used). They are most diverse in
desert regions of the world, as they are typically associated with solitary
bee and wasp species, which are also most diverse in such areas. Species of the largest
subfamily, Chrysidinae, are the most familiar; they are generally
cleptoparasites, laying their eggs in host nests, where their larvae consume
the host egg or larva while it is still young, then consuming the provisions.
Chrysidines are distinguished from the members of other subfamilies in that
most can curl into a defensive ball, in a process known as conglobulation.
This ability is shared with pill bugs, pill millipedes (which are often
mistaken for pill bugs), and armadilloes. Members of the other subfamilies
are parasitoids, of either sawflies or walking sticks, and cannot fold up
into a ball. Chrysididae are large and brilliantly
metallic, usually green or blue, with coarse sculpturing. They are known as ruby wasps, gold wasps
and cuckoo wasps. They are mainly
solitary external parasitoids of vespoid and sphecoid Hymenoptera, although
several are inquilines in the nests.
Most species attack hosts that form their nests or cells in exposed
places, such as mud cells on walls, in crevices, etc., or those in hollow
plant stems (Clausen 1940/62). However,
some species confine themselves to hosts that burrow in the soil. Chrysis
shanghaiensis Smith in 1940 was the single representative of the family
known to be parasitic on larvae of Lepidoptera. Clausen (1940) believed that generally Chrysididae should
probably be considered more injurious than beneficial because of attack on
hosts that store their nests with injurious insects and on hosts that are
beneficial because of their habit of gathering nectar or pollen. However, few species are abundant enough
to be of much economic importance. Hymenopterous adult hosts of
Chrysididae are often strong fighters, which may have been responsible for
the development of defensive measures by the parasitoid, which are identical
to those employed by many other animals having a heavy carapace. Females when disturbed or attacked often
roll themselves into a compact ball, remaining immobile and thus shielding
the vulnerable body parts from injury (Clausen 1940/62). In chrysidids the head is
hypognathous, the antennal flagellum has 11 segments; the pronotum has an
anterior flange, and the propleuron is concealed in dorsal view (Finnamore
& Brothers 1993). The pronotum
has the posterolateral apex usually well separated from the tegula, but
sometimes it touches the latter. The
prosternum is small; metasoma with 5 or less exposed terga, rarely with a
trace of the 6th. Sexual dimorphism
is usually very slight. Both sexes
are macropterous, rarely brachypterous or apterous; brachypterous and apterous
species do not have the deep ventral constriction between the meso- and metathorax. This family has more than 3,000
species in four subfamilies:
Amiseginae, Chrysidinae, Cleptinae, and Loboscelidiinae. Their greatest diversity is in temperate
deserts of both hemispheres. Adults
are predominantly metallic green, violet and/or red, seldom brown or dull
black. If brown or black then
sometimes they are partly dull red.
Larvae are parasitoids of the eggs or of the mature larvae of other
insects or they are cleptoparasites in insect nests. Pupation occurs within the host egg,
cocoon, or nest. . Most species are primary,
solitary, ecto- or endoparasitoids.
Immature stages usually develop on or within larval bees and nesting
wasps, but some species feed as inquilines on the provisions stored in cells
intended for the host larvae. The
family is of importance to biological control. Biology & Behavior
A detailed account of Chrysis shanghaiensis was given by
Piel (1933a) and Parker (1936). It is
a solitary external parasitoid of mature larvae of the oriental moth, Monema flavescens Wlk., within its
hard egg-like cocoon, in China and southern Japan. This cocoon is too hard to be penetrated by the female's
flexible ovipositor. Instead, she
bites a small hole in it with her mandibles, during which she slowly rotates
the body about the point of attack.
The surface markings at the point of penetration are thus in the form
of radiating lines. When the hole is
large enough, she turns around, inserts her ovipositor and stings the host
larva in the thoracic region, causing permanent paralysis. It is thought that stinging serves to halt
development to the pupal stage rather than larval immobilization. The egg is then laid loosely on the body,
after which the female again applies her mandibles to the orifice, scraping
from the surface of the cocoon material that, with the pellets set aside at
the time the opening was made, is mixed with an oral secretion which serves
to seal the aperture. Parasitized cocoons
are recognized by the radiating lines surrounding the point of penetration,
which extend outward 1-2 mm. This
whole process from cocoon penetration to final sealing takes ca. 1 hr.
(Clausen 1940/62). First instar larvae are active,
and while feeding, use the bifurcate caudal process as a brace against the
cocoon wall. The mature larva spins a
silken, golden cocoon within that of the host, and the meconium is discharged
through the strands of the partly formed cocoon into the posterior region of
the host cocoon, which contains the remains of the Monema larva. Parasitoids
always emerge from the anterior end of the host cocoon. The cycle from egg to adult takes ca. 6
weeks, of which 2-4 days are required for egg incubation and a minimum of 11
days for the pupal stage. The larval
feeding period is followed by a rest period of about equal length. In south China, the duration of the cocoon
stage of the first generation is ca. 21-25 days. Adults are long-lived, and females may persist in the field for
several months. However, reproductive
capacity is low. Parker in the
laboratory obtained an average of only 11.3 eggs per female, and in China
field parasitization reaches 50%.
There are two generations per year in south China, which corresponds
to the host cycle, but only a single generation developed in the laboratory
in Massachusetts. Hibernation is as
mature larvae. Chrysididae, which are parasitic
on Hymenoptera usually, attack the host in the mature larval or prepupal
stage and are not dependent at any time on the provisions contained in host
cells. Hicks (1933) found C. pacifica
Say to oviposit at any stage of development of the larva of its host, Alcidamea brachyodonta Ckll., but the 1st instar larva delays its attack
until the host cocoon is spun and the prepupa is reached. Pleurocera
viridis Guer. and Tetrachrysis carinata Guer. oviposit through the concrete-like cell wall of
the Odynerus cell only after the
cocoon of the latter has formed (Janvier 1933). Penetration of the cell wall takes 1-3 hrs of effort with the
ovipositor. C. viridula L.,
attacking Odynerus, also usually
chooses the less protected cells for oviposition and may lay eggs in those
which are still open (Chapman 1869).
In closed cells, there is some indication that the mandibles are used
in making the perforation. Six to 10
eggs are placed on a host, with the surplus is destroyed by the larva
hatching first. Behavior of C. lusca var. concinna Grib. differs decidedly from
the above species (Bordage 1913). The
egg is laid shortly after that of the host, Sceliphron, and 1st instar parasitoid larvae and host engage in
combat, after which the survivor develops on the prey contained in the
cell. If the host egg fails to hatch,
the Chrysis larva dies without
touching the food. This suggests that
the Chrysis larva dies without
touching the food supply, and that the species is an obligate predator on the
1st instar larva of Sceliphron, and
after this host has been consumed its food requirements are met by the
spiders with which the cell is stocked.
In Chrysis dichroa Dhlb. developing in cells of O. rufohiria
Latr. in Europe, the egg is laid in the cell before the latter is closed and
on the food material at the opposite side from that occupied by the Osmia egg (Ferton 1923). The parasitoid egg hatches shortly before
the host, and though a number of eggs may be laid in a cell, only one larva
survives past the 1st instar. Usually
the parasitoid will not attack the Osmia
until larval development is complete, although sometimes the egg may be
destroyed. Similar habits were
recorded for C. prodita, parasitic on O. saundersii
Vach. A species of Chrysididae known to
develop as an internal parasitoid is Pseudochrysis
neglecta Shuck. (Maneval 1932). The 1st instar larva penetrates the body
of the partly grown larva of Osmia villosa Schnck. and develops
coincidentally with it. Internal
feeding takes 20 days, and the host body contents are entirely consumed. All species spin a cocoon within
the host cell, which in most cases is also within the host cocoon. C.
viridula first forms a mirrorlike
diaphragm across the center of the host cocoon, that separates it from the
host remains. In this chamber the
parasitoid spins its cocoon. This characteristic
seems common to the family. Developmental period from hatching
to the completion of feeding is rather short for most species. Egg incubation takes 2-5 days, and larval
feeding up to 30 days. The minimum is
for C. ignita, which completes feeding within 6 days after
oviposition. In summer broods, a
resting period intervenes before pupation.
A number of species have only one generation per year, but this seems
correlated with the host. Hibernation
occurs as mature larvae in the cocoon.
The period of occurrence of adults in the field is often much shorter
than that covered by the nesting activities of hosts, and a portion of the
host population thus escapes attack. Janvier (1933) described mating in
T. carinata in Chile. The
male emerges earlier than the female and is able to detect the presence of
his mate while she is still within the host cell. When such a cell is found, the male attacks the cell wall with
his mandibles, eventually making a way into the interior. He then tears open the cocoon, and the
female is seized by the thorax and dragged out of the cell, where mating
takes place. For detailed descriptions of immature stages of
Chrysididae, please see Clausen (1940/62). = = = = =
= = = = = = = = References: Please refer
to <biology.ref.htm>, [Additional
references may be found at: MELVYL Library
] Finnamore,
A.T. & D. J. Brothers. 1993. Superfamily Chrysidoidea (pp. 130-160). In GOULET,
H. & HUBER, J. (eds). Hymenoptera of the World: an identification
guide to families. Research Branch, Agriculture Canada, Ottawa, Canada,
668 pp. Kimsey,
L. S. 2006. California Cuckoo Wasps in the Family Chrysididae
(Hymenoptera. Univ. of Calif Press.
ISBN: 978-0-520-09857-2
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