Hemiptera of Canada.

The Canadian Hemiptera (Sternorrhyncha, Auchenorrhyncha, and Heteroptera) fauna is reviewed, which currently comprises 4011 species, including 405 non-native species. DNA barcodes available for Canadian specimens are represented by 3275 BINs. The analysis was based on the most recent checklist of Hemiptera in Canada (Maw et al. 2000) and subsequent collection records, literature records and compilation of DNA barcode data. It is estimated that almost 600 additional species remain to be discovered among Canadian Hemiptera.

The order , the true bugs, is a relatively large order. Worldwide there are an estimated 106,970 described species (Henry 2017, Bartlett et al. 2018, Hardy 2018). The recognised Canadian fauna (Table 1) has been greatly expanded since the review by Scudder (1979), with an increase of 937 species above the 3079 then known. The checklist of Canadian (Maw et al. 2000) provided comprehensive lists and distributions for all species recognised at that time. Here we present updated totals, including a number of additional unpublished records represented by PageBreakspecimens in the Canadian National Collections of Insects, Arthropods and Nematodes (CNCI) in Ottawa. Gwiazdowski et al. (2015) presented a detailed analysis of all Hemipteran DNA barcodes available for the Canadian fauna.

Table 1.

Census of in Canada.

Taxon1	No. species reported in Scudder (1979)2	No. species currently known from Canada3	No. BINs4 available for Canadian species	Est. no undescribed or unrecorded species in Canada	General distribution by ecozone4A	Information sources5
Suborder Sternorrhyncha
Superfamily Psylloidea						CNCI
Aphalaridae 6	50	37 (1)	19	10	all ecozones but Arctic
Calophyidae 6	?	1	0	0	Mixedwood Plains
Liviidae 6	4	14 (3)	6	2	all ecozones but Arctic
Psyllidae 6	35	52 (5)	65	20	all ecozones but Arctic
Triozidae	18	25 (1)	13	10	all ecozones but Arctic
Superfamily Aleyrodoidea
Aleyrodidae	3	13 (4)	40	40	all ecozones south of taiga	CNCI
Infraorder Aphidomorpha
Superfamily Adelgoidea
Adelgidae	22	18 (5)	14	1	all ecozones but Arctic
Superfamily Aphidoidea
Aphididae	650	847 (164)	758	100	all ecozones	CNCI
Superfamily Phylloxeroidea
Phylloxeridae	6	8 (2)	11	4	Pacific Maritime, Mixedwood Plains, Boreal Plains (1 sp.)
Infraorder Coccomorpha
Superfamily Coccoidea
Asterolecaniidae	1	2 (2)	0	0	Pacific Maritime, Mixedwood Plains
Coccidae	15	26 (12)	7	5	all ecozones, mostly south of Arctic
Cryptococcidae	?	2 (2)	0	0	Mixedwood Plains, Atlantic Maritime
Dactylopiidae	1	1	0	0	Prairies
Diaspididae	16	30 (10)	4	10	all ecozones, mostly south of taiga
Eriococcidae	3	3 (2)	2	0	Pacific Maritime, Mixedwood Plains, Atlantic Maritime
Kermesidae	0	4	0	1	Mixedwood Plains
Margarodidae	4 7	0	0	0
Matsucoccidae 7	?	2	0	0	Mixedwood Plains, Atlantic Maritime
Ortheziidae 8	3	5	2	0	all ecozones but Arctic
Pseudococcidae	13 9	25 (9)	11	10	all ecozones, mostly south of taiga	Newton et al. 2011; CNCI
Putoidae 9	?	2	0	0	Montane Cordillera, Boreal Cordillera
Rhizoecidae	0	1	0	2	Pacific Maritime	CNCI
Steingeliidae 7	?	1 (1)	0	0	Mixedwood Plains
Xylococcidae 7	?	1	0	0	Atlantic Maritime
Total Sternorrhyncha	844	1120 (223)	955	215
Suborder Auchenorrhyncha
Superfamily Fulgoroidea
Acanaloniidae 10	?	2	2	0	Mixedwoods Plains
Achilidae	17	19	15	3	all ecozones but Arctic
Caliscelidae	7	11	7	0	mostly south of boreal
Cixiidae	25 11	31	14	5	all ecozones but Arctic
Delphacidae	81	138 (1)	102	30	all ecozones
Derbidae	14	21	17	3	all ecozones south of taiga; most in Mixedwood Plains
Dictyopharidae 12	4	8	5	1	widespread south of taiga
Flatidae	1	3	3	0	Mixedwoods Plains
Issidae	3 10	2	1	0	Mixedwoods Plains
Kinnaridae 11	?	1	0	0	Western Interior Basin
Infraorder Cicadomorpha
Superfamily Cicadoidea
Cicadidae	9	21	10	7	mostly south of taiga, Taiga Plains (1 sp.)
Superfamily Cercopoidea
Aphrophoridae 13	?	23 (4)	19	2	all ecozones but Arctic
Cercopidae	33 13	1	0	0	Mixedwoods Plains
Clastopteridae 13	?	12	8	2	all ecozones south of taiga
Superfamily Membracoidea
Cicadellidae	800	1097 (76)	1144	150	all ecozones	Dmitriev 2018, specimens in CNCI
Membracidae	70	101 (1)	65	20	widespread south of boreal, few in Boreal Shield and Boreal Plains	Dmitriev 2018
Total Auchenorrhyncha	1064	1491 (82)	1412	223
Suborder [?] Heteroptera						Scudder 2008 and references included therein, Scudder 2012, Roch 2017
Infraorder Enicocephalomorpha
Superfamily Enicocephaloidea
Aenictopecheidae	0	1	0	0	Boreal Plains (single collection)
Enicocephalidae 14	1	1	2	1	Mixedwood Plains, Atlantic Maritime
Infraorder Dipsocoromorpha
Superfamily Dipsocoroidea
Ceratocombidae 15	1	1	7	5	Pacific Maritime, Mixedwood Plains
Schizopteridae	0	1 (1)	0	0	Pacific Maritime
Infraorder Gerromorpha
Superfamily Gerroidea
Gerridae	19	22	13	1	all ecozones but Arctic
Veliidae	6	8	6	0	all ecozones south of taiga
Superfamily Hebroidea
Hebridae	4	5	2	0	all ecozones south of taiga
Superfamily Hydrometroidea
Hydrometridae	1	1	1	0	Pacific Maritime, Prairies, Mixedwood Plains, Atlantic Maritime
Superfamily Mesovelioidea
Mesoveliidae	2	2	2	0	all ecozones south of taiga
Infraorder Nepomorpha
Superfamily Corixoidea
Corixidae	72	79	57	2	all ecozones but Arctic
Superfamily Naucoroidea
Naucoridae	0	1	1	0	Mixedwood Plains
Superfamily Nepoidea
Belostomatidae	3	4	2	0	all ecozones but Arctic
Nepidae	7	4	6	1	Mixedwood Plains, southern Boreal Shield
Superfamily Notonectoidea
Notonectidae	12	12	10	0	all ecozones but Arctic
Pleidae	2	1	1	0	Mixedwood Plains, southern Boreal Shield
Superfamily Ochteroidea
Gelastocoridae	1	1	1	0	Pacific Maritime, Prairies, Mixedwood Plains
Ochteridae	0	1	0	0	Mixedwood Plains
Infraorder Leptopodomorpha
Superfamily Saldoidea
Saldidae	36	38	23	2	All ecozones, mostly south of Arctic
Infraorder Cimicomorpha
Cimicoidea
Anthocoridae	4116	39 (7)	36	1	widespread south of taiga
Cimicidae	4	7	3	0	widespread south of taiga
Lasiochilidae 16	?	1	0	0	Mixedwood Plains
Lyctocoridae 16	?	6	2	0	all ecozones south of taiga
Superfamily Naboidea
Nabidae	12	22 (3)	19	2	all ecozones south of Arctic
Superfamily Microphysoidea
Microphysidae	0	3 (3)	1	0	near Pacific and Atlantic ports of entry
Superfamily Miroidea
Miridae	60117	706 (57)	414	100	mostly south of Arctic, widespread
Tingidae	46	52 (6)	30	10	all ecozones south of taiga
Superfamily Reduvioidea
Reduviidae	2618	29 (3)	20	0	all ecozones south of taiga
Infraorder Pentatomomorpha
Superfamily Aradoidea
Aradidae	47 19	51	13	2	all ecozones but Arctic
Superfamily Coreoidea
Alydidae	10	9	7	0	all ecozones but Arctic
Coreidae	11	15	14	0	all ecozones but Arctic
Rhopalidae	9	19 (1)	14	2	all ecozones but Arctic
Superfamily Lygaeoidea
Artheneidae	0	1 (1)	1	0	all ecozones south of taiga
Berytidae 20	3	5 (1)	6	0	all ecozones south of boreal
Blissidae 21	?	6	4	0	all ecozones south of boreal
Cymidae 21	?	5	4	0	all ecozones south of taiga
Geocoridae 21	?	10	5	0	all ecozones but Arctic
Heterogastridae 21	?	2 (1)	0	0	Pacific Maritime
Lygaeidae	100 21	27 (1)	18	2	all ecozones, most south of Arctic
Oxycarenidae 21	?	5 (1)	1	0	all ecozones but Arctic
Pachygronthidae 21	?	3	4	1	all ecozones but Arctic
Piesmatidae	1	4	1	0	all ecozones south of taiga
Rhyparochromidae 21	?	71 (10)	52	7	all ecozones but Arctic
Superfamily Pentatomoidea
Acanthosomatidae	5	5 (1)	3	0	all ecozones but Arctic
Cydnidae	7	12 (1)	13	3	Pacific Maritime, Mixedwood Plains
Pentatomidae	63 22	77 (1)	68	5	all ecozones but Arctic
Scutelleridae	9	13	9	2	all ecozones but Arctic, mostly south of taiga
Thyreocoridae 23	9	11	12	2	all ecozones but Arctic, mostly south of taiga
Total Heteroptera	1171	1400 (100)	908	151
Total Hemiptera	3079	4011 (405)	3275	589

Classification follows Ouvrard (2018, ), Favret (2018, ), García Morales et al. (2016, ), Bartlett et al. (2018, ), and Henry (2017, ). Some families not recognised by Scudder (1979) but which contain species included by him within other families, are indicate by ? in this column. Numbers in parentheses indicate the number of non-native species included in the total. Phytophagous species known only from indoor plants are not included. Barcode Index Numbers, as defined by Ratnasingham and Hebert (2013). See figure 1 in Langor (2019) for a map of ecozones. The baseline data for all groups is the most recent comprehensive checklist of in Canada (Maw et al. 2000). Sources given here are for subsequent additions to the known fauna. Collection abbreviation: CNCI, specimens in Canadian National Collection of Insects, Arachnids and Nematodes. As the delineation of families of has changed since Scudder (1979), the number of species reported in 1979 for each family are not comparable to current totals with the exception of . In Scudder (1979), the count for included , , and ; no Canadian species remain in . Misspelled as Arthezidae in Scudder (1979). In Scudder (1979), the count for included . In Scudder (1979), the count for included . In Scudder (1979), the count for included . Treated under in Scudder (1979); there are no Canadian species of s.str.In Scudder (1979), the count for included and . was listed under in Scudder (1979). was treated as part of in Scudder (1979). In Scudder (1979), the count for included and . Scudder (1979) reported on (600 spp.) and (1 spp.) separately; however, we have combined these counts for 1979 under . Scudder (1979) reported on (13 spp.), (3 spp.), and (10 spp.) separately; however, as these are all currently included in , we have combined the count for 1979. Scudder (1979) reported on (46 spp.) and (1 spp.) separately; however, we have combined these counts for 1979 under . Scudder (1979) reported this family as . In Scudder (1979), the count for included , , , , , , , and . Scudder (1979) reported on (61 spp.) and (2 spp.) separately; however, we have combined these counts for 1979 under . Scudder (1979) reported this family as .

A further 590 species are estimated to occur in the country, with the majority expected in the large families , , and . Estimates of the number of unrecorded species for the less diverse families is based mainly on known but undescribed species and presence of species in adjacent climatologically and ecologically similar parts of the United States, and known distributions of host plants. Molecular data and analysis of host plant usage provides evidence of additional cryptic diversity in the more speciose phytophagous groups. For some families, presence of unnamed clusters in the DNA barcode data suggests additional species, assuming that in most cases Barcode Index Numbers (BINs), as defined by Ratnasingham and Hebert (2013), correspond to one or more species (Gwiazdowski et al. 2015).

The classification used here follows Psyl’list (Ouvrard 2018) for , Aphid Species File (Favret 2018) for , ScaleNet (García Morales et al. 2016) for , Bartlett et al. (2018) for higher classification of , Bartlett et al. (2014) for species level delimitation in , Dmitriev (2018) for species level delimitation in , and Henry (2017) for higher level classification of . There have been several changes in higher level classification since Scudder (1979). , no longer recognised as a formal taxon, is now treated as two suborders, namely and . Although not followed here, some authors (after Sorensen et al. 1995) separate the into suborders Clypeorrhyncha and Archaeorrhyncha. Among , many new families of scale insects have been erected; species in Canada formerly included in are now dispersed among , and ; was formerly included in . Schemes for the subdivision of family , such as that of Heie (1980) (and used in the checklist of Maw et al. 2000), have been proposed, but largely ignored in the absence of a clear consensus on the relationships among aphid subgroups. Within the , the , , and are now recognised in Canada, with their species removed from the , , and , respectively. The broadly constituted has been divided, with most Canadian species now placed in the and . In the , most former lygaeid subfamilies have been given family status so that of Scudder (1979) is now represented by eight families (Henry 1997); the further segregation of and (Sweet 2000) from is not recognised here. and have been separated from . On the other hand, now includes , includes , and includes and .

The 419 non-native species of represents a significant proportion of the total fauna. In , about 19% of the species are non-native. An overview of the non-native aphid fauna of North America was provided by Foottit et al. (2006) and updated by Skvarla et al. (2017). The non-native of Canada (about 7% of the total fauna) were treated by Scudder and Foottit (2006).

Worldwide, the are represented by about 18,690 species (Hardy 2018), with about 2950 species in North America (approximate composite number based on Foottit et al. 2006, García Morales et al. 2016, Skvarla et al. 2017, Mallory 2018, Ouvrard and Martin 2018). Currently, 1120 species of are known from Canada compared to 834 in 1979, and it is expected that a further 215 species will be eventually found in the country (Table 1).

In Canada, the and are relatively well known. Foottit and Maw (1997, 2014) contributed syntheses of the Yukon and grassland faunas of . Aphids and adelgids are well represented by DNA barcodes (Foottit et al. 2008, 2009a, b), and, in general, barcode diversity in these groups corresponds well to morphological species concepts. However, several currently recognised aphid species are represented by more than one BIN, as defined by Ratnasingham and Hebert (2013). In two such cases, subsequent morphological analysis and addition of other genetic loci has resulted in the recognition of new species (Foottit et al. 2010, Foottit and Maw 2018). Conversely, members of several aphid species groups are not distinguishable by COI sequence divergence (Foottit et al. 2008).

The have not been subjected to extensive taxonomic or faunal analysis in Canada, except for work by Hodkinson (e.g., Hodkinson 1976) in British Columbia and Alberta. The identifiable forms of (adult female) and of (immatures) are sessile or subterranean and thus not captured by the usual general collecting methods. Consequently, the national fauna and regional distribution of species in these two groups are poorly known, and even limited efforts can yield new records. Kozár et al. (1989) identified several species of scale insects new to Canada based on brief collecting efforts in southern British Columbia. In a recent study of ant–sternorrhynch associations at a single grassland site in Alberta, two of the four species of found were newly recorded for Canada (Newton et al. 2011). The number of available BINs (see Table 1), largely based on untargeted sampling by the Biodiversity Institute of Ontario (University of Guelph), has indicated that current knowledge greatly under-represents the true fauna of and if BIN diversity can be considered a good approximation of species diversity in these groups.

Worldwide there are about 43,024 species of (Bartlett et al. 2018), but an estimate for North America is currently not available. In Canada, Hamilton (1997, 2014) analysed the cicadellid fauna of the Yukon and the Canadian Prairie Ecozone, respectively, Gareau (2008) documented that of Quebec, and Wilson (1997) treated the Yukon . The taxonomic status of several auchenorrhynch groups has been updated. A number of papers by Hamilton (e.g., Hamilton 1983, 1994, 1998) have revised many groups of . As well, the large and difficult tribe has been completely revised by Dmitriev and Dietrich (2007, 2009, 2010). The PageBreakPageBreakPageBreakPageBreakPageBreakPageBreak were completely revised and a handbook published by Hamilton (1982). Progress on the includes a review of the North American fauna (Bartlett et al. 2014), which provides illustrated keys to all genera including the first comprehensive key to delphacid genera in the region. The known diversity of Canadian has increased since Scudder (1979), mostly as a result of taxonomic progress and improved knowledge of distributions. Currently, 1491 species are known from Canada compared to 1060 in 1979, and it is expected that a further 223 species will be eventually found in the country (Table 1). Most of the increases are in line with estimates of unrecorded species provided by Scudder (1979). The highest proportional increase is among the from nine to 21 recorded species; this increase is entirely due to improved knowledge of distribution (Hamilton 2010, Sanborn and Phillips 2013) as little taxonomic work has been done on the family in Canada. The highest numerical increase is among the with an increase of 297 species; this is due to a combination of significant taxonomic research, greatly increased knowledge of distributions, and a small number of recently introduced species. We expect this family to hold the largest number of still unrecorded species (estimated at 150 species), particularly among the under-studied and under-collected subfamily .

Significant progress has been made in DNA barcoding of the Canadian . Data for 691 species have been released (Foottit et al. 2014, Gwiazdowski et al. 2015) and unpublished data for additional species is available in Barcode of Life Data System (Ratnasingham and Hebert 2007). A simple comparison between the number of BINs and recorded species suggests that more than half the Canadian species have been barcoded in most families, and an impressive 91% of the highly diverse . However, caution is required in interpreting these numbers. Single BINs have been shown to include multiple morphologically distinct species in a number of cicadellid genera (Foottit et al. 2014). Conversely, preliminary examination of BINs for the suggests that single species may be represented by multiple BINs. Thus, the number of BINs may not be predictive of the number of distinct species within these groups.

There are about 45,254 described species of in the world. The most recent published comprehensive catalog for the group in North America (Henry and Froeschner 1985) includes 3834 species. About 1400 species are currently known to occur in Canada compared to 1171 in 1979, and it is expected that a further 151 species will be eventually added (Table 1). Most families of this suborder are relatively well known in the country. However, representatives of two families have been found in Canada only recently: in 2010 (Scudder 2010a) and in 2016 (Scudder and Štys 2016). Roch (2017) recently documented the of Quebec. Detailed analyses of the faunas of the Yukon, grasslands, Atlantic Maritime Ecozone and Montane Cordillera Ecozone have appeared (Scudder 1997, 2010b, 2011, 2014), and the aquatic and semiaquatic of Canadian peatPageBreaklands and marshlands and the aquatic of the prairies and parklands were documented by Scudder (1987) and Scudder et al. (2010). Kelton (1980) provided a handbook of the of the Prairie Provinces. A major on-line database of the mirid fauna of North America (Schuh 2002–2013) includes records for a major portion of the holdings of the CNCI. DNA barcodes for the 334 species of drawn from CNCI (mainly Canadian species) were presented by Park et al. (2011) and reanalysed by Gwiazdowski et al. (2015).

The predicted number of constitutes the bulk of the estimate for overall, but this number is speculative and may be an underestimate if there are a significant number of undetected cryptic species within the more speciose genera.

Summary and opportunities

Despite the significant increase in knowledge of in Canada since 1979, a substantial amount of the country’s biodiversity still awaits discovery. Some groups of are relatively well documented in Canada, while others are quite poorly known. However, even in the well-studied, but highly diverse phytophagous families (such as and ), there is probably unrecognised cryptic diversity associated with host plants and geographic variation. Several large genera in these families, such as , continue to present taxonomic difficulties (Schwartz and Foottit 1998) and opportunities for application of new approaches and technologies. Because many species of are current or potential pests, continuing research on detection, identification, quarantine and management of these groups will be required.