Aquatic
Insects of Michigan
by
Ethan Bright, Museum of Zoology Insect Division and School of Natural
Resources and Environment
University of Michigan
Aquatic Hymenoptera (Wasps) of Michigan
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 |
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
Trichopria - parasitizes ephydrid (Hydrellia), sciomyzid (Atrichomelina, Dictya, Elgiva, Sepedon ), and psephenid (Psephenus) pupae
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) eggsTetrastichus coerulescens Ashmead
Hexacola - parasitizes ephydrid (Parydra) larvae-pupae
Kleidotoma - parasitizes ephydrid (Parydra, Scatella) larvae-pupaeKleidotoma 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
Caraphractus - parasitizes notonectid (Notonecta), gerrid (Gerris), calopterygid (Calopteryx), and dytiscid (Dytiscus, Agabus ) eggs
Anoplius - parasitizes Dolomedes (Araenea: Pisauridae) adult spiders
Gyrinophagus - parasitizes gyrinid (Gyrinus, Dineutes) larvae in pupal cases
Sisyridivora - parasitizes sisyrid (Climacia) larvae and pupae in cocoons
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 (EB) - Last updated: October 25, 2007 (EB)