Aquatic Insects of Michigan

by Ethan Bright, Museum of Zoology Insect Division and School of Natural Resources and Environment
University of Michigan

Aquatic Hymenoptera (Parasitic Wasps) of Michigan - Identification

[under construction]

A number of parasitic wasps have come adapted for aquatic existence by attacking various life stages (principally eggs, larvae and/or pupae) of aquatic insect groups, especially those of Heteroptera and holometabolous orders (e.g., Lepidoptera, Coleoptera, etc.).

Information regarding the occurrence of aquatic Hymenoptera in Michigan is currently in preparation. Please email the author if you have records or information regarding this group in Michigan.

Below is a key to adult hymenoptera genera known to parasitize aquatic insects found in Michigan. Ecological information - and the key - is adapted from Bennett (2007), and will be updated with surveying of deposited collection material.

1a	a. Wing venation reduced	2
	b. Front wings usually with no enclosed cells, but, if present, with <5 enclosed cells
	c. Wings usually with long marginal fringe
	d. Hind wings veinless, or with one vein (enclosed cells absent)
	also: Rarely wingless
1b	a. Wing venation well-developed	9
	b. Front wings with >5 enclosed cells
	c. Without a long marginal fringe, at least on the anterior margins
	d. Hind wings with >2 veins, and at least one enclosed cell
2a(1a)	Hind femur enlarged and with a toothed or denticulate ventral margin	Chalcididae
2b	Hind femur not enlarged, and without a toothed ventral margin	3
3a(2b)	Tarsi 3-segmented	Trichogrammatidae
	also: Parasites of insect eggs
3b	Tarsi 4- or 5-segmented	4
4a(3b)	Tarsi 4-segmented	5
4b	Tarsi 5-segmented	6
5a(4a)	a. Marginal vein short, terminating within the first third of the wing's length	Mymaridae
	b. Stigmal vein absent
	c. Body not metallic
	also: Parasites of insect eggs
5b	a. Marginal vein long, extending beyond one-half the length of the wing	Eulophidae
	b. Stigmal vein present
	c. Body with metallic reflections or highly colored
6a(4b)	Antennae inserted on the shelf at middle of face	Diapriidae
6b	Antennae not arising from the shelf at middle of face	7
7a(6b)	Antennae with 2 distinctly smaller segments (anelli) between the pedicel and the first funicle segment	Pteromalidae
	also: Together the anelli thinner, and usually shorter, than the first funicle segment
7b	Antennae without 2 distinctly smaller segments between the pedicel and the first funicle segment	8
8a(7b)	a. Scutellum with 2 pits at the base, and an elevated pit ("cup") on the disk	Figitidae
	b. Forewing without a stigmal vein
	c. Abdomen compressed
8b	a. Scutellum without an elevated cup	Scelionidae
	b. Forewing with a stigmal vein
	c. Abdomen depressed
9a(1b)	a. Hindwing with an anal lobe	Pompilidae, Anoplius
	b. Trochanters 1-segmented
	c. Antennae with <15 segments and curled apically
	also: parasitizes Dolomedes (Araenea: Pisauridae) adult spiders
9b	a. Hindwing without an anal lobe	10
	b. Trochanters 2-segmented
	c. Antennae with > 15 segments
10a(9b)	Forewing with 2 recurrent veins (second recurrent vein is a crossvein in the apical lower half of the wing disk)	Ichneumonidae
10b	Forewing with 1 recurrent vein (no crossvein in the apical lower half of the wing)	Braconidae

Braconidae (Ichneumonoidea)

Ademon - parasitizes ephydrids (Hydrellia) larvae-pupae
Aphanta - parasitizes ephydrids (Hydrellia) pupae
Asobara - parasitizes ephydrids (Parydra) larvae-pupae
Bracon (=Microbracon) - parasitizes noctuids (Archanara) larvae
Chaenusa - parasitizes ephydrids (Hydrellia) eggs-pupae
Chorebidea - parasitizes ephydrids (Hydrellia) pupae
Chorebidella - parasitizes ephydrids (Hydrellia) pupae
Chorebus - parasitizes ephydrids (Hydrellia) pupae
Dacnusa - parasitizes ephydrids (Hydrellia) pupae
Opius - parasitizes ephydrids (Hydrellia) larvae-pupae
Phaenocarpa - parasitizes sciomyzids (Antichaeta) pupae

Diapriidae

Trichopria - parasitizes ephydrid (Hydrellia), sciomyzid (Atrichomelina, Dictya, Elgiva, Sepedon ), and psephenid (Psephenus) pupae

Eulophidae (Chalcidoidea)

Aprostocetus - hyperparasite in lestid (Lestes) eggs
Mestocharis - parasitizes dytiscid (Dytiscus) eggs
Psephenivorus - parasitizes psephenid (Psephenus) prepupae, pupae
Tetrastichus - hyperparasite in, and parasite of, lestid (Lestes) eggs

Tetrastichus coerulescens Ashmead

Fatigidae (Cynipoidea)

Hexacola - parasitizes ephydrid (Parydra) larvae-pupae
Kleidotoma - parasitizes ephydrid (Parydra, Scatella) larvae-pupae

Kleidotoma parydrae

Ichneumonidae (Ichneumonoidea)

Apsilops (=Neostricklandia, =Trichocryptus, =Trichestema) - parasitizes pyralids (Occidentalia, Chilo, Schoenobius, Nymphula) larvae - Michigan species: Apsilops bicolor (Cushman), Apsilops hirtifrons (Ashmead), Apsilops sericata (Viereck)
Bathythrix (=Hemiteles) - parasitizes gyrinids (Gyrinus) larvae in pupal cases - Michigan species: Bathythrix triangularis (Cresson)
Cremastus - parasitizes pyralids (Occidentalia, Chilo, Nymphula) larvae and pupae - Michigan species: Cremastus bilineatus Cushman, Cremastus incompletus (Provancher), Cremastus orbus Dreisbach - IN
Medophron - parasitizes dytiscids (Agabus, Dytiscus) pupae
Mesoleptus - parasitizes sciomyzids (Antichaeta) pupae - Michigan species: Mesoleptus declivus (Provancher), Mesoleptus incompletus Provancher
Oecotelma (=Hemiteles) - parasitizes gyrinids (Gyrinus) larvae in pupal cases
Phygadeuon - parasitizes sciomyzids (Antichaeta) pupae - MIchigan species: Phygadeuon aciculatus Provancher
Pleurogyrus (=Hemiteles) - parasitizes gyrinids (Gyrinus) larvae in pupal cases
Sulcarius - parasitizes limnephilids (Limnephilus) in larvae in cases
Therascopus (=Eriplanus) - parasitizes gyrinids (Gyrinus) larvae in pupal cases

Mymaridae (Chalcidoidea)

Caraphractus - parasitizes notonectid (Notonecta), gerrid (Gerris), calopterygid (Calopteryx), and dytiscid (Dytiscus, Agabus ) eggs

Pompilidae (Vespoidea)

Anoplius - parasitizes Dolomedes (Araenea: Pisauridae) adult spiders

Pteromalidae (Chalcidoidea)

Gyrinophagus - parasitizes gyrinid (Gyrinus, Dineutes) larvae in pupal cases
Sisyridivora - parasitizes sisyrid (Climacia) larvae and pupae in cocoons

Scelionidae (Proctotrupoidea)

Telenomus - parasitizes tabanid (Tabanus, Chyrsops) eggs
Thoron - parasitizes nepid (Nepa, Ranatra) eggs
Tiphodytes - parasitizes gerrid (Gerris, Trepobates, Limnoporus) eggs

Trichogrammatidae (Chalcidoidea)

Hydrophylita - parasitizes coenagrionid (Ischnura) eggs
Lathromera - parasitizes lestid (Lestes) eggs
Paracentrobia - parasitizes lestid (Lestes) eggs
Prestwichia - parasitizes nepid (Nepa, Ranatra ), dytiscid (Dytiscus) eggs
Trichogramma - parasitizes water mite (Hydracarina), sialid (Sialis), corydalid (Corydalus), and sciomyzid (Sepedon, Elgiva,Tetanocera) eggs

Key to adults
(modified from Pinto 2006)

1a	a. Scutellum with at least 2 pair of setae (anterior pair may be very short), midlobe of mesoscutum usually with 2 or more pair of setae	Prestwichia
	b. Eyes light to dark red in color
	also: Maxillary palp present; antennae with 4 postanellar segments, and; antennae without placoid sensilla (PLS) on surface; mesosomal dorsum sculptured, at least with obsolescent reticulae; fore wings very narrow, about 7x as long as wide, and densely setose
1b	a. Scutellum and midlobe of mesoscutum each with 1 pair of setae	2
	b. Eyes black in color
2a(1b)	a. Fore wing very narrow, 5-10x as long as wide	Hydrophylita
	b. Antenna with 2 funicular segments, both longer than wide
	c. Female club with two large spatulate sensilla
2b	a. Forewing considerably broader, considerably less than 5x as long as wide	3
	b. Antennae with funicle variable in structure, or entirely absent
	c. Female club without large spatulate sensilla
	also: Hind tibial spur short, apically pointed, at most slightly longer than the first tarsomere
3a(2b)	Antennae with only 1 elongate postanellar segment	Trichogramma (Trichogramma) in part
3b	Antennae with more than 1 postanellar segment	4
4a	Antenna with a 2-segmented funicle and a 1-segmented club	Trichogramma in part
	also: Fore wing with SV clearly diverging from the anterior margin and MV, never reduced to a small appendix; Fore wing disk noticeably setose, hind wing disk with two setal tracks (posterior track may be complete or partial), its anterior fringe considerably shorter than the posterior fringe; antenna with F2 not narrowed at apex, not bottle-shaped; Fore wing with RS1 track present behind the stigmal vein; premarginal vein (PM) with 2 setae
4b	Antenna with funicle present or not, but with a club distinctly 3-segmented	5
	also: maxillary palp 1-segmented
5a(4b)	Antennae with funicle absent	Lathromeris
	also: Antennal club 5-segmented, club segment 1 width subequal to the maximum club width; female antennal club with a terminal process at the apex; fore wing with RS1 absent, discal setation moderately dense at most; male metasomal tergum VI (and often VII) with modified areas
5b	Antennae with funicle present	6
6a(5b)	Fore wing venation sinuate, greatest curvature distally where marginal vein (MV) gradually curves away from the anterior wing margin onto the stigmal vein (SV)	Trichogramma (Vanlisus) in part
6b	Fore wing venation not sinuate, with the MV ending abruptly distally, not gradually curving onto the SV	Paracentrobia
	also: Antennal club distinctly 3-segmented; 2 anelli present; Male sternum VIII modified into two narrow, strap-like appendages; anntenal funicular segments lacking PLS; sunicle distinctly narrower than the base of the club, funicular segment 1 about as wide as long, segment 2 transverse, distinctly broader than long; male genitalia with ADG incorporated into GC

References

Bennett AMR. 2007. Aquatic hymenoptera, pp. 673-686 in Merritt RW, Cummins KW, Berg MB, An Introduction to the Aquatic Insects of North America, Fourth Edition. Kendall/Hunt Publishing Company, Dubuque, Iowa, USA.
Pinto JD. 2006. A review of the New World genera of Trichogrammatidae (Hymenoptera). Journal of Hymenoptera Research 15(1): 38-163.

Page created: June 26, 2006; Last edited: October 25, 2007 (EB)