HETEROPTERA

G.G.E. Scudder

SYSTEMATIC REVIEW

So far about 610 species of Heteroptera are recorded from the Montane Cordillera ecozone (Appendix). Of these 36 (5.8%) are aquatic, 14 (2.3%) semiaquatic, and the remaining 570 (91.9%) terrestrial. In total 161 (26%) are predators, and the remaining 459 (74%) are plant feeders.

In the Montane Cordillera, 54 species of true bugs are potentially rare and endangered (Scudder 1992, 1994, 1996), 47 (87%) of these occurring in the South Okanagan Basin ecosection and threatened as a result of loss of shrub-steppe, grassland, riparian and aquatic habitats. Seven true bug species are listed as endemic to the ecozone.

Infraorder GERROMORPHA

This infraorder includes all the semi-aquatic Heteroptera. Five families, all predaceous, are found in the ecozone.

In the water treader family Mesoveliidae, there is just one species, Mesovelia mulsanti White. This is found in marshes and swamps, and occurs on ponds covered with emergent or floating vegetation. Macropterous specimens are rare, the species overwintering in the egg stage (Scudder 1987).

The Velvet water bug family Hebridae is represented by a single species, Merragata hebroides White. This can usually be found by trampling the vegetation or moist detritus at the edge of aquatic habitats. It overwinters as an adult.

The marsh treader family Hydrometridae, is also represented by a single species, Hydrometra martini Kirkaldy. The species is usually found in swamps and marshes, or along the margins of ponds (Scudder 1987). It overwinters as an adult, and is listed as potentially rare and endangered in British Columbia, being known so far only from Lytton (Scudder 1961, 1977).

Two species of small water strider in the family Veliidae occur in the ecozone. They occur in marshes and live at the edge of ponds (Scudder 1987), and are often seen running across the water surface among emergent vegetation. These Microvelia species exhibit expansion skating or “skimmings” to avoid capture, releasing fluid into the water surface to lower the surface tension and thus propelling themselves with a sudden speed in almost any direction (Andersen 1982).

The Gerridae is represented by 3 general and 9 species of water strider, namely all taxa that are reported in British Columbia (Scudder 1977). All overwinter as adults. Most occur on lentic environments, but the species of Aquarius prefer flowing water. The Gerris species often coexists on ponds and lakes (Scudder 1971; Jamieson 1973), and exhibit microhabitat specialization and species packing (Spence 1979, 1981, 1983; Spence and Scudder 1980; Spence et al. 1980; Nummelin et al. 1984). The two species of Limnoporus hybridize broadly across the ecozone (Spence 1990; Sperling and Spence 1991).

Infraorder DIPSOCOROMORPHA

In the Montane Cordillera, only one species Ceratocombus vagans McAtee & Malloch, in the family Ceratocombidae has been recorded. Ceratocombids are probably predaceous, occur in leaf litter and other ground detritus, and are uncommon.

The giant water bug family Belostomatidae is represented by 2 species, Belostoma flumineum Say and Lethocerus americanus Leidy. Both species overwinter as adults, and are voracious predators, which normally feed on tadpoles and insects, but will also attack prey items many times their own size, including fish and frogs. Eggs of Lethocerus are laid above water on vegetation and other protruding objects. In Belostoma, eggs are laid on the backs of males, which carry them until they hatch.

There is a single species of water scorpion, Ranatra fusca Palisot, in the family Nepidae. This species occurs in marshes and ponds (Scudder 1987), where it inhabits submerged vegetation. Eggs are deposited in floating vegetation, and adults overwinter.

The water boatmen or Corixidae are represented by 8 genera and 26 species, which are quite difficult to tell apart. However, the monograph on Western Hemisphere Corixidae by Hungerford (1948) will enable most entomologists to separate the species, but more recent papers by Jansson (1972, 1978) are needed to identify the species of Cenocorixa and Callicorixa.

Corixid eggs are laid on various underwater objects, and most species overwinter as adults. They are often seen swimming under the ice or trapped in air pockets within it. While the majority of species live in freshwater, many inhabit inland saline lakes (Scudder 1969, 1976, 1983). Corixids generally disperse readily by flight, both by day and night. Stridulation is used as a mating signal in many genera, with songs being species and sex specific (Jansson 1973, 1976).

Two genera and 7 species of backswimmers in the family Notonectidae occur in the ecozone, representing all species found in British Columbia (Scudder 1977). Two of these Notonecta spinosa Hungerford and N. unifasciata andersoni Hungerford, are potentially rare and endangered and confined to the South Okanagan Basin ecosection (Scudder 1994, 1996).

Infraorder CIMICOMORPHA

Eight families in this infraorder occur in the ecozone, and with 121 genera and 360 species, so far identified, this is the largest component of the heteropteran fauna.

Bedbugs belonging to the family Cimicidae are rarely encountered. Four species are present in the ecozone, with the cosmopolitan Cimex lectularius Linnaeus usually associated with human dwellings, but now fortunately not very common. The bat bedbug Cimex pilosellus Horvath is not uncommon, and in the Dry Belt of British Columbia has been taken associated with the long-legged myotis (Myotis volans longicrus (True)) (Horvath 1910), the silver haired bat (Lascionycteris noctivagnas LeConte) and the big brown bat (Eptesicus fuscus (Beauvois) (Spencer 1934). The specimens of C. pilosellus from Anarchist Mt. may prove to be a distinct species when chromosome studies can be undertaken (Usinger 1966).

Oeciacus vicarius Horvath is primarily a parasite of cliff swallows, but it has been reported from barn swallow nests (Zack 1990). Hesperocimex coloradensis List has only been collected once from the nest of the Red shafted flicker (Colaptes cafer (Gmelin)) at Summerland (Scudder 1961), and is potentially rare and endangered in British Columbia (Scudder 1994, 1996). A fifth bedbug species Cimex latipennis Usinger & Ueshima, usually associated with bats, is listed from British Columbia in the key to Cimex species in Usinger (1966), but I cannot trace the source of this record. The species might occur in the Montane Cordillera ecozone, and should be looked for.

There are 11 genera and 23 species of minute pirate bugs in the family Anthocoridae so far detected in the ecozone, one of which Anthocoris nemoralis (Fabricius) was introduced into the Okanagan Valley from Switzerland in 1963, to control the pear psylla (Psylla pyricola Forster) (McMullen 1971). Along with other species of Anthocoris, it is now an established predator on this pest (McMullen and Jong 1967). However, available data suggest that the introduced A. nemoralis causes competitive displacement of the other native predatory Anthocoris species from pear orchards in the second half of July each year (Fields and Beirne 1973).

The family Lyctocoridae, which until recently has been considered within the Anthocoridae (Kelton 1978), is represented by 4 species. Two of these are endemic and listed as potentially rare and endangered.

The predatory assassin bugs of the family Reduviidae are typical inhabitants of the warmer parts of the ecozone, with 8 genera and 10 species detected to date. The elongate Barce fraterna (Say) occurs at the base of vegetation and can be collected in pitfall traps, whereas other species such a Rhynocoris ventralis (Say) and Sinea diadema (Fabricius) are usually found on vegetation. The cosmopolitan Reduvius personatus (Linnaeus) is typically found in or associated with human dwellings and buildings (Scudder 1992).

Phymata americana metcalfi Evans in the family Phymatidae, is the only ambush bugs so far identified in the ecozone. Although there are keys to the species of Phymata (Evans 1931; Kormilev 1962), species identification is difficult. As the common name suggests, these bugs are ambush predators, usually seen waiting on flower heads, particularly goldenrod (Solidago spp.) or other yellow inflorescence on which they are well camouflaged.

The largest family of true bugs in the Montane Cordillera ecozone are the plant bugs or Miridae. With 85 genera and 283 species so far identified, they are one of the most difficult groups taxonomically. Prairie taxa have been monographed by Kelton (1980), but there is no comprehensive review of the British Columbia fauna, although one is in preparation (Schwartz and Scudder, in prep.).

The tribes Dicyphini, Deraeocorini and Pilophorini, and a few species in other tribes are predaceous. Deraeocoris brevis (Uhler), D. fasciolus Knight, Blepharidopterus provancheri (Burque) and Campylomma verbasci (Meyer-Dür) are important predators of the pear psylla (Psylla pyricola) in Okanagan pear orchards (McMullen and Jong 1967). The mullein bug Compylomma verbasci is also a predator on the eggs of the codling moth (Cydia promonella (L.)), but its feeding habits limit its use as an egg predator, because it overwinters in apple orchards and feeds early in the season on both arthropods and young developing fruit (Knight et al. 1997). In the Okanagan Valley it is capable of causing serious crop losses in ?Delicious’ cultivars (Madsen et al. 1975; Thistlewood et al. 1989). As a result, an increasing number of apple orchards are being treated for this pest (Reding and Beers 1995; Knight et al. 1997). Campylomma verbasci is one of eight introduced miride present in the ecozone.

Another introduced mirid that can be a pest is the alfalfa plant bug Adelphocoris lineolatus (Goeze) (Beirne 1972; Hedlund and Graham 1987). However, it is Lygus species that are the greatest pest on alfalfa in the ecozone (Arrand 1960; Beirne 1972), although species of Plagiognathus, especially P. medicagus Arrand can also be a pest (Arrand 1958; Beirne 1972). As noted by Beirne (1972), although most species of Lygus pests on alfalfa have been recorded as Lygus borealis (Kelton), L. elisus Van Duzee or L. lineolaris (Palisot), until recently many species have been confused, owing to the taxonomic difficulty of this genus. The new monograph on Lygus by Schwartz and Foottit (1998) should help clarify this situation.

The majority of the plant bugs are phytophagous, with both monophagous and polyphagous species being present. It is the polyphagous species that are usually the major pests. This is well illustrated in the mirid pests of fruit crops in the ecozone. Kelton (1982) reports that the tarnished plant bug (Lygus lineolaris (Palisot)) occurs on at least 20 fruit crops in the province. The pear plant bug, Lygocoris communis (Knight) is also reported from 19 fruit crops in British Columbia (Kelton 1982).

Plant bugs in the genus Lopidea display patterns of contrasting red-black or yellow-black coloration, which suggests that these insects are aposematic (Asquith 1991). Experiments reported by McIver and Lattin (1990) and McIver and Tempelis (1993) show that at least Lopidea nigridea Uhler is distasteful to some visually orientating arthropod predators.

Members of the tribes Hallodapini and Pilophorini and some other plant bugs are myrmecomorphic (McIver and Stonedahl 1993; Scudder 1997). In a number of the plant bug species it is the females that are ant mimics. Coquillettia insignis Uhler (McIver 1987; McIver and Stonedahl 1987a) and Orectoderus obliquus Uhler (McIver and Stonedahl 1987b) are the best known Batesian mimics, but others in the ecozone include O. arcuatus Knight, O. montanus Knight, Mimoceps insignis Uhler, Mecomma angustatum (Uhler), M. gilvipes (Stål) and Sericophanes heidemanni Poppius.

At least 21 species of plant bugs in the ecozone are listed as potentially rare and endangered (Scudder 1994, 1996). Most of these occur in the South Okanagan Basin ecosection and are associated either with riparian habitats or the Dry Belt, particularly the Antelope-brush (Purshia tridentata) ecosystem.

Four genera and 12 species of damsel bugs belonging to the family Nabidae are recorded. All nabids are generalist predators, feeding on other insects, and thus potentially useful in natural pest control. However, plant feeding is also possible in the genus Nabis (Ridgway and Jones 1968; Stoner 1972). Most damsel bugs occur on vegetation, but Pagasa fusca (Stein) is a ground dweller and myrmecomorphic (McIver and Stonedahl 1993).

The lace bugs or Tingidae, with 8 genera, 23 described species and evidently one undescribed species, are the second most species-rich family in this infraorder in the ecozone. All lace bugs are phytophagous, and most are host plant specific. The genus Acalypta occur on mosses and is usually not found in general collecting. Gargaphia opacula Uhler is confined to Antelope-brush (Purshia tridentata) in the South Okanagan Basin ecosection, and is potentially rare and endangered owing to loss of habitat

Infraorder LEPTOPODOMORPHA

The only family in this infraorder present is the Saldidae. Commonly called shore bugs, these are all predators. Usually found in littoral areas, some of the 6 genera and 23 species in the ecozone occur well away from damp habitats. Ioscytus politus (Uhler), which is listed as potentially rare and endangered, is confined to the margins of saline lakes in the South Okanagan.

Infraorder PENTATOMOMORPHA

There are 19 families in this infraorder in the Montane Cordillera. Seven of these are recently classified as families, as a result of the cladistic analysis of the Lygaeoidea by Henry (1997a).

The Aradidae or flat bugs, monographed in Canada by Matsuda (1977), feed on fungi under bark and are cryptically coloured. Two genera and 28 species have been identified from the ecozone to date.

The Alydidae or broad-headed bugs have myrmecomorphic immature stages, and are phytophagous, feeding mainly on leguminous plants. Three genera and 6 species occur in the ecozone.

Four genera and 5 species of Coreidae have been collected in the Montane Cordillera. All corieds are phytophagous, with the squash bug Anasa tristis (De Geer) being a well known pest in southern Ontario and southern Quebec (Beirne 1972), but rarely so in British Columbia. The western conifer seed bug, Leptoglossus occidentalis Heidemann is a coniferous seed pest and has caused seed losses of between 36% and 41% (Koerber 1963; Hedlin et al. 1980; Ruth 1980; Ruth et al. 1982). It is known to deplete seed in Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco), ponderosa pine (Pinus ponderosa Dougl.), white pine (Pinus albicaulis Engelm.) and lodgepole pine (Pinus contorta Dougl.) seed orchards (Strong et al. 1998). It overwinters as an adult, and at times can occur in large aggregations in man-made structures in the ecozone (Blatt 1994).

Another bug that can occur in homes and buildings as large overwintering masses of adults is the western boxelder bug Boisea rubrolineata (Barber). These can cause homeowners much anxiety, because of their defecation and obnoxious odour when crushed. The other 5 genera and 9 species of rhopalids in the ecozone are less obvious. Four species that are confined to the South Okanagan Basin ecosection are listed as potentially rare and endangered.

The striking stilt bugs or Berytidae, recently monographed in the western hemisphere by Henry (1997b), are phytophagous. Scudder (1991) summarized the distribution and biology of the 3 genera and 3 species that are recorded in the ecozone, and provides a key to these taxa. Hoplinus echinatus (Uhler), which apparently feeds on a large variety of plants, including Madia sp., Phacelia sp. and Castilleja sp. (Henry 1997b), is listed as potentially rare and endangered, being known only from the Wasa and Osoyoos areas (Scudder 1994, 1996).

The 32 genera and 61 species of seed bugs in the ecozone that previously were placed in the Lygaeidae, are now contained in 8 separate families (Blissidae, Cymidae, Geocoridae, Heterogastridae, Lygaeidae, Oxycarenidae, Pachygrowthidae, Rhyparochromidae) (Henry 1997a). The species of Geocoris are often predators, and Nysius species can be crop pests (Beirne 1972). Three of the seed bugs in the ecozone are introduced European species, their distribution being summarized by Asquith and Lattin (1991).

Gastrodes intermedius Usinger is an endemic species in the ecozone, and this plus 8 other seed bugs are listed as potentially rare and endangered. Most of these occur in the South Okanagan Basin ecosection.

Two species of Acanthosomatidae are present. These two phytophagous stink bugs have Salix as the main host.

Of the 5 genera and 5 species of root feeding burrowing bugs or Cydnidae, four occur primarily in the South Okanagan, and 3 are listed as potentially rare or endangered. They are not commonly encountered, unless looked for by pitfall trapping.

The subfamily Asopinae of the stink bug family Pentatomidae contains 4 genera and 7 species. All are predaceous. The other 16 genera and 35 species of pentatomid are phytophagous. Some such as Dendrocoris pini Montandon occur on conifers, whereas others such as Aelia americana Dallas, Coenius delius (Say) and Neottiglossa spp. are found mostly in grasslands. Sciocoris microphthelnus Flor. can often be found feeding on the seed heads of Dryas drummondii Richards (Scudder 1997).

Four genera and 7 species of shield bugs belonging to the family Scutelleridae occur in the ecozone. These phytophagous bugs, especially species of Eurygaster can be pests.

The Thyreocoridae, commonly called negro bugs are represented by 2 genera and 5 species. They occur on grasses, weeds and shrubs, with Corimelaena extensa Uhler often found feeding on the seed heads of mullein (Verbascum thapsus L.)

Two species of Piesma (family Piesmatidae) have been found so far. These phytophagous insects feed mainly on members of the Amaranthaceae and Chenopodiaceae. Elsewhere in North America, Piesma cinereum (Say) can be quite a pest, serving as a vector of the virus causing Sugar Beet Savoy (Drake and Davis 1958), but there are no reports of this species as a pest in the ecozone.