Comparative Analysis and Systematic Mapping of the Labial Sensilla in the Nepomorpha (Heteroptera: Insecta)

Table 2

Detailed description of the number, shape, and distribution of the labial mechanosensilla and contact-chemoreceptive sensilla of the species representing nepomorphan taxa. Species marked with an asterisk (*) are illustrated. Characters of all featured species have been analyzed and compared.

Types of mechanosensilla and contact-chemoreceptive sensilla; length of the sensilla
Taxa: species	Distribution of sensilla on the labial segments
	(D); I	(V); I	(D); II	(V); II	(D); III	(V); III	(D); IV	(V); IV	TRS1 and TRS2; in distal part,; (D) + (L) side, IV	TRS1 and TRS2 in distal part, (V) side, IV
Nepinae
Curicta granulosa; Borborophyes mayri; Nepa cinerea	INV	INV	(N)SQS; (S)BAS; (S)TBS; 1 COS	(N)SQS; (S)BAS	(N)SQS; (S)BAS	(N)SQS; (S)BAS; (S)TBS	(N)PDS1; (N)PDS2; (S)CH1; (S)CH2	(S)PDS1; (S)PDS2; (S)CH1; (S)CH2	(D)4TRS1 + 2TRS2; (L)2TRS1 + 2TRS2	4TRS1; 2TRS2
Lacccotrephes japonensis* (Figure 9)	INV	INV	(N)SQS; (S)BAS; (S)TBS; 1 COS	(N)SQS; (S)BAS	(N)SQS; (S)BAS	(N)SQS; (S)BAS; (S)TBS	(N)CBS; 1 COS	(S)CBS	(D)4TRS1 + 2TRS2; (L)2TRS1 + 2TRS2	3TRS1; 1TRS2
Ranatrinae
Cercotmetus asiaticus	INV	INV	(S)PDS1; (S)PDS2	(S)PDS1; (S)PDS2	(N)PDS1; (N)PDS2	(S)PDS1; (S)PDS2	(N)PDS1; (N)PDS2; (S)CH1	(S)PDS1; (S)PDS2; (S)CH1; (S)CH2; (S)CH3	(D) = 2TRS1 + 2TRS2; (L) = 2TRS1 + 2TRS2	2TRS1; 4TRS2
Ranatra chinensis* (Figure 10)	INV	INV	(N)PDS1; (N)PDS2	(N)PDS1; (N)PDS2	(N)PDS1; (N)PDS2	(N)PDS1; (N)PDS2	(N)PDS1; (N)PDS2; (S)CH1	(S)PDS1; (S)PDS2; (S)CH1; (S)CH2; (S)CH3	(D)4TRS1 + 2TRS2; (L)4TRS1 + 2TRS2	4TRS1; 1TRS2
Belostomatinae
Belostoma flumineum* (Figure 11); Dienostoma dilatatum	(N)CH2	(S)CH3	(S)CH1; (N)CH2; (N)CH3	(S)CH1; (S)CH2; (S)CH3; 1 COS	(S)CH1; (S)CH2; (S)CH3	(S)CH1; (S)CH2; (S)CH3	(N)CUS; (N)PES; 1 COS	(N)CUS; (N)PES	(D)2TRS1; (D)1TRS2	3TRS1; 1TRS2
Hydrocyrius colombiae (Figure 12)	(S)CH3	(S)CH3	(S)CH1; (S)CH2; (S)CH3	(S)CH1; (S)CH2; (S)CH3	(S)CH2; (N)CH3	(N)CH3	(N)CUS; (N)PES; 1 COS	(N)CUS; (N)PES	(D)4TRS1; (D)3TRS2	9TRS1; 2TRS2
Appasus major	(S)CH3	(S)CH3	(S)CH2; (S)CH3	(S)CH1; (S)CH3	(S)CH1; (S)CH3	(S)CH1; (N)CH3	(N)CUS; (N)PES; 1 COS	(N)CUS; (S)PES	(D)3TRS1; (D)2TRS2	5TRS1; 2TRS2
Limnogeton fieberi* (Figure 13)	(N)CH3	(N)CH3	(N)CH3; (N)CH2; (S)CH1	(N)CH3; (N)CH2	(N)CH3; (N)CH2; (S)CH1	(N)CH3; (N)CH2	(N)PES	(N)PES	(D)5TRS1; (D)3TRS2	6TRS1; 2TRS2
Lethocerinae
Lethocerus deyrollei* (Figure 14)	INV	INV	(N)CH2; (N)CH1	(N)CH3; (S)CH1	(N)CH2; (N)CH3	(S)CH2; (S)CH3	(N)CUS; (N)PES; 1 COS	(N)CUS; (N)PES	(D)4TRS1; (D)3TRS2	9TRS1; 3TRS2
Ochteridae
Ochterus piliferus* (Figures 15(a)–15(d)); Ochterus marginatus* (Figures 15(e)–15(g))	(N)CH1; (N)CH2	(N)CH1; (N)CH2	(N)CH1; (N)CH2	(N)CH1; (N)CH2	(S)CH3	(S)CH3	(N)CUS; (N)PES; 1 COS	(N)CUS; (N)PES	Lack	2TRS2
Gelastocorinae
Gelastocoris oculatus* (Figure 16)	(N)HLS; (N)CH2	(N)HLS; (N)CH2	(N)HLS; (S)FRS; 3 COS	(N)HLS	(S)CH1; (S)CH2; (N)CH3	(S)CH2; (N)CH3	(N)PES; (N)CUS; 1 COS	(N)PES; (N)CUS	Lack	3TRS2
Nerthrinae
Nerthra nepaeformis* (Figure 17); Nertha macrothorax	(S)CH2; (S)CH3	(S)CH2; (S)CH3	(S)CH2; (S)CH3; 3s COS	(S)CH3	(S)CHD; (S)CH1; (S)PES; (S)CUS	(S)PES; (S)CUS	(N)PES; (N)CUS; 1 COS	(N)PES; (N)CUS	Lack	2TRS2
Aphelocheiridae
Aphelocheirus aestivalis* (Figure 18); Aphelocheirus variegatus	(S)CH2; (S)CH3	(S)CH2; (S)CH3	(N)STS; (S)CH3; (S)CH2; 1 COS	(S)CH3; (S)CH2	(N)STS; (N)PES	(S)STS; (S)PES; (S)CH2	(N)PES; (N)CUS; 1 COS	(N)PES; (N)CUS	Lack	2TRS2
Cheirochelinae
Cheirochela feana* (Figure 19(e))	(S)CH3	(S)CH3	(S)CH3; 1 COS	(S)CH3	(N)PES; 3TRS1; 2TRS2	(S)PES	(N)PES; 1 COS	(N)PES	Lack	9TRS1; 1TRS2
Gestroiella limnocoroides* (Figures 19(f)–19(i))	(S)CH3	(S)CH3	(S)CH3; 1 COS	(S)CH3; 1 COS	(N)PES; 3TRS1; 1TRS2	(S)PES	(N)PES; 1 COS	(N)PES	Lack	3TRS1; 2TRS2
Coptocatus kinabalu	(S)CH3	(S)CH3	(S)CH3; 1 COS	(S)CH3	(N)CH3; 2TRS1	(S)CH3	(N)PES; 1 COS	(N)PES	Lack	4TRS1; 1TRS2
Coptocatus oblongulus	(S)CH3	(S)CH3	(S)CH3; 1 COS	(S)CH3	(S)CH3; 2TRS2	(S)CH3	(N)PES; 1 COS	(N)PES	Lack	3TRS1; 2TRS2
Tanycricos longiceps	(S)CH3	(S)CH3	(S)CH3; (S)CH2; (S)CH1; 1 COS	(N)CH1	(S)CH3; 2TRS2	(S)CH3	(N)PES; 1 COS	(N)PES	Lack	4TRS1; 2TRS2
Laccocorinae
Laccocoris hoogstraali* (Figures 20(a)–20(d))	INV	INV	(S)CH3; (S)CH2; 1 COS	(S)CH3; (S)CH2	(N)PES; 4TRS1; 1TRS2	(S)CH3	(N)PES; 1 COS	(N)PES	Lack	3TRS1; 2TRS2
Helocoris humeralis (Figures 20(e)-20(f))	INV	INV	(S)CH3; (S)CH2; 1 COS	(S)CH3; (S)CH2	(N)PES; 7TRS1; 1TRS2	(S)CH3	(N)PES; 1 COS	(N)PES	Lack	4TRS1; 2TRS2
Limnocorinae
Limnocoris lutzi* (Figure 21)	INV	INV	6 COS; PLE	(N)CH2; PLE	(S)MPS; 3TRS2; PLE	(S)CH3; PLE	(N)MPS; 1 COS	(N)MPS	Lack	4TRS1; 1TRS2
Cryphocricinae
Cryphocricos hungerfordi* (Figure 22)	INV	INV	(N)CH2; (S)CH3; 1 COS	(N)CH2	(S)MPS; TRS-invisible	(S)CH3	(N)MPS; 1 COS	(N)MPS	Lack	3TRS1; 2TRS2
Ambrysus ocidentalis* (Figure 23)	(S)CH2	(S)CH1	(S)CH3; 1 COS	(S)CH3; 1 COS	(S)MPS; 4TRS1; 1TRS2	(S)CH3	(N)MPS; 1 COS	(N)MPS	Lack	5TRS1; 1TRS2
Naucorinae
Ilyocoris cimicoides	INV	INV	(S)CH2; (S)CH3; 1 COS	(S)CH3	2TRS1	(S)CH3	(N)MPS; 1 COS	(S)MPS (S)CH3	Lack	10TRS1; 2TRS2
Pelocoris femoratus	INV	INV	(S)CH2; (S)CH3; 1 COS	(S)CH2; (S)CH3	(S)CH2; 3TRS1; 2TRS2	(S)CH3	(N)MPS; 1 COS	(S)MPS (S)CH3	Lack	4TRS1; 4TRS2
Macrocoris rhantoides	INV	INV	(S)CH2; (S)CH3; 1 COS	(N)CH2; (S)CH3	3TRS1; 2TRS2	(S)CH3	(N)MPS; 1 COS	(S)MPS	Lack	6TRS1; 3TRS2
Naucoris maculatus* (Figures 24(a)-24(b))	INV	INV	(S)CH2; (S)CH3; 1 COS	(N)CH2 (S)CH3	(S)CH2; 2TRS1	(S)CH3	(S)MPS; 1 COS	(S)MPS	Lack	4TRS1
Namtokocoris siamensis* (Figures 24(c)–24(e))	INV	INV	(S)CH1; (S)CH2; 1 COS	(S)CH2	(S)CH1; (N)CH2; 4TRS1	(S)CH2	(S)MPS; 1 COS	(S)MPS	Lack	4TRS1; 2TRS2
Neomacrocoris handlirschi (Figures 24(f)-24(g))	INV	INV	INV	(S)CH3	12TRS1	(S)CH2	(S)MPS; 1 COS	(S)MPS	Lack	invisible
Pleidae
Paraplea frontalis* (Figure 25)	INV	INV	(N)CH3; 2 COS	(S)CH3; 1 COS	(S)CH2; (S)CH3	1 CH3	4 CH3	1 CH3	(D)1TRS1	3TRS1
Helotrephidae
Helotrephes semiglobosus	(N)CH1	(N)CH1	(N)CH2	(N)CH2; 1 COS	(S)CH2	(S)CH2	(S)CH2; 1 COS	(S)CH2	(D)1TRS1; (D)1TRS2	2TRS1
Hydrotrephes visayasiensis* (Figure 26)	(N)CH1	(N)CH1	(N)CH2	(N)CH2; 1 COS	(S)CH2	(N)CH2	(S)CH3; 1 CH2; 1 CH1	(S)CH3; 2 CH1	(D)1TRS1; (D)1TRS2	2TRS1; 2TRS2
Hydrotrephes balnearius	INV	INV	(N)CH3	(N)CH3; 1 COS	(S)CH2	(N)CH2; (S)CH3	(S)CH3	(S)CH3	(D)1TRS1; (D)1TRS2	1TRS1; 2TRS2
Tiphotrephes indicus	(N)CH3	(N)CH3	(N)CH3	(N)CH3; 1 COS	(S)CH3; (S)CH2	(S)CH3; (S)CH2	(S)CH3	(S)CH3	(D)3TRS2	3TRS2
Anisopinae
Anisops camerunensis	(S)CH3	(S)CH3	(N)CH3; 1 COS	(N)CH1	(S)CH1; (S)CH3	(S)CH3	(S)CH3	(S)CH3	(D)2TRS1; (D)3TRS2	6TRS1; 2TRS2
Anisops sardea	(S)CH3	(S)CH3	(N)CH3; 1 COS	(N)CH1	(S)CH1; (S)CH3	(S)CH3	(S)CH3	(S)CH3	(D)2TRS1; (D)2TRS2	6TRS1; 2TRS2
Buenoa uhleri* (Figure 27)	INV	INV	(S)CH2; (S)CH3; 1 COS	(S)CH2	(S)CH2; (S)CH3	(S)CH2; (S)CH3	(N)CH3; (S)CH2	(N)CH3; (S)CH2	(D)1TRS1; (D)2TRS2	2TRS1
Notonectinae
Notonecta glauca* (Figure 28)	(S)CH2; (S)CH3	(N)CH1	(S)CH1; (S)CH2; (S)CH3; 1 COS	(S)CH2; (S)CH3	(S)CH1 (S)CH3	(N)CH1; (N)CH2	(N)CH3	(N)CH3	(D)1TRS1	6TRS1; 3TRS2
Enithares bergrothi	(S)CH3	(S)CH3	(S)CH2; (S)CH3; 1 COS	(N)CH1	1 CH1; (S)CH2; (S)CH3	(S)CH2	(S)CH3	(S)CH3	(D)3TRS1; (D)2TRS2	6TRS1
Nychia sappho	(S)CH3	(S)CH3	In-visible	(S)CH2; (S)CH3	(S)CH3	(S)CH3	(S)CH3	(S)CH3	(D)1TRS1 + 1TRS2	2TRS1; 1TRS2
Corixidae	Modified labium (unsegmented)
Corixinae
Agraptocorixa hyalinipennis; Hesperocorixa linnaei; Ectemnostegella montana; Corixa punctata; Corixa dentipes*; (Figure 29)	(N)P + (N)RBS1 + (N)RBS2 + (N)CH1 + (N)CH2 + (N)CH3						Stenocorixinae: Stenocorixa protrusa; (N)P + (N)RBS1 + (N)RBS2 + (N)CH1 + (N)CH2 + (N)CH3; Cymatiinae: Cymatia coleoptrara* (Figure 30); (N)RBS1 + (N)RBS2 + (N)PES + (N)CH1 + (N)CH2 + (N)CH3; Diaprepocoridae: Diaprepocoris zealandiae* (Figure 31); (N)P + (N)RBS1 + (N)RBS2 + (N)CH1 + (N)CH2 + (N)CH3; Micronectidae: Micronecta quadristrigata* (Figure 31); (N)P(N)RBS1 + (N)RBS2 + (N)CH1 + (N)CH2 + (N)CH3

Symbol key: (D): dorsal side; (V): ventral side; (L): lateral side; (N): numerous sensilla; (S): several sensilla; INV: sensilla and I segment were invisible; 1–6 number of pairs COS and CH; I: first labial segment; II: second labial segment; III: third labial segment, IV: fourth labial segment. Abbreviation of names of the labial sensilla are explained in Table 1 and in the results.