Tetrigimyia minor, a new genus and species of Tachinidae (Diptera) parasitic on Formosatettix larvatus (Orthoptera: Tetrigidae) in Japan
Shima, Hiroshi
Takahashi, Hajime
Zootaxa
2011
2921
39
46
8FDTQ
[151,368,151,177]
Insecta
Tachinidae
Tetrigimyia
Animalia
Diptera
3
42
Arthropoda
species
minor
sp. nov.
Holotypemale, Akagawa-onsen, Takeda City, Mts. Kuju, Oita Pref., Japan, 27.iv.2009(date of adult emergence), ex Formosatettix larvatus, H. Takahashi( BLKU). FIGURES 2–6.Terminalia of Tetrigimyia minor sp. nov.2.Male epandrium, cerci and surstylus in dorsal view (hairs omitted). 3.Same in lateral view (hairs on epandrium omitted). 4.Male hypandrium, pregonite, postgonite and phallus in lateral view. 5.Male 5th sternite in ventral view (hairs on left side omitted). 6.Female terminalia in lateral view. Scale: 0.1 mm. Paratypes: All ex Formosatettix larvatus, 2 males, Karasawa, Hanno City, Saitama Pref., 25.iv.2009(date of adult emergence), I. Wada ( BLKU); 5 males 4 females, Akagawa, Takeda City, Oita Pref., date of adult emergence as follows: 13,23,24. iv.2009, 17,19.vii.2009, 5.ix.2009, 31.x.2009, 1,11. xi.2009, H. Takahashi (KUM). Other material examined.All ex Formosatettix larvatus, date showing adult emergence; Natsui, Tainai City, Niigata Pref., 2 females, 13.viii.2008, H. Takahashi; Karasawa, Hanno City, Saitama Pref., 1 male 1 female, 25.v.2009, I. Wada; Mt. Takao, Hachioji City, Tokyo, 1 female, 2.vii.2009, H. Takahashi; Mt. Daisen, Tottori Pref., 2 males 2 females, 16,19. v.2009, H. Takahashi; Akagawa-onsen, Takeda City, Mts. Kuju, Oita Pref., 3 males 4 females, 23.iv.2009, 1 female, 24.iv.2009, 2 males 1 female, 25.iv.2009, 3 males 5 females, 27.iv.2009, 1 female, 28.iv.2009, 1 female, 17.vii.2009, 2 males, 19.vii.2009, 2 females, 23.vii.2009, 1 female, 1.viii.2009, 1 female, 30.x.2009, 1 male, 1.xi.2009, 1 male, 3.xi.2009, 1 male, 2 females, 7.xi.2009( BLKU, KUM). Host. Formosatettix larvatusBei-Bienko( Orthoptera, Tetrigidae).
Etymology.The specific name refers to the small body size of this species.
Distribution. Japan(Honshu & Kyushu).
Biology. Formosatettix larvatusis apterous and its adults and larvae are found in dark undergrowth of elm woods eating dead and decaying leaves. Tetrigimyia minoris oviparous; females lay planoconvex elliptical eggs (0.5 mm long, 0.25 mm wide) on the ventrolateral portion of host abdomen. Parasitized adults or larvae were found in April (Akagawa, Oita Pref.), May (Karasawa River, Hanno City and Mt. Daisen, Tottori Pref.), and June and October (Akagawa). This tachinid appears to have at least two generations a year, adults appearing in late spring and again in summer. It is possible that the tachinid overwinters as a 2nd or 3rd instar in the host’s body. Percentages of parasitism of this fly were high at Akagawa, but rather low at Karasawa and Mt. Daisen ( Table 1). The first instar tachinid larva emerges through the operculum of the egg within a week after oviposition and penetrates into the host haemocoel through the abdominal intersegmental membrane, moving at least 1.6 mm apart from the egg. Second and third instars form a respiratory funnel attached to a host abdominal spiracle. Dissection of dead hosts revealed that there were more than one (up to five) tachinid larvae per host. Usually only one mature larva emerged from a host and pupated, but in some cases two successfully emerged and eclosed. TABLE 1.Percentage parasitism of Tetrigimyia minoron Formosatettix larvatusin 2009. Locality Collection date F. l a r v a t u sunparasitized parasitized Total larvae adults Akagawa April 11Adult males 6 1 1 2 9 Adultfemales 8 1 1 1 10Larval males 3 2 - 5 Larval females 1 4 - 5 Percentage parasitism: 37.9% Akagawa July 7Adult males 4 - - 4 Adultfemales 4 - 2 6 Larval males 13 4 - 17Larval females 10 4 - 14 Percentage parasitism: 24.4% Akagawa October 11Adult males 1 - - 1 Adultfemales 1 - - 1 Larval males 4 8 - 12Larval females 5 5 - 10 Percentage parasitism: 54.2% Karasavwa May 11Adult males 7 1 1 1 9 Adultfemales 11 - - 11 Percentage parasitism: 10.0% Mt. Daisen May 2Adult males 11 2 1 - 13Adult females 11 - - 11 Larval males 2 - - 2 Larval females 3 - - 3 Percentage parasitism: 6.9%
1Parasitized adults without entrance holes of parasitoid larvae on their bodies are considered to have been parasitized as larvae.