Chrysoperla Steinmannı 1964

Henry, Charles S., Taylor, Katherine L. & Johnson, James B., 2019, A new lacewing species of the Chrysoperla carnea species-group from central Asia associated with conifers (Neuroptera: Chrysopidae), Journal of Natural History 53 (21), pp. 1277-1300 : 1279-1286

Genus Chrysoperla Steinmannı 1964

Type Species: Chrysoperla carnea (Stephens, 1836)

Chrysoperla duellii sp. nov. ( Figures 1 (a), 2(b), 3(a), 3(b) and 4; Tables 1 , 2 and 3 )

Holotype

Male : KYRGYZSTAN: Ottuk (N42.31 E76.32), 1603 m, 7 July 2016, coll. D. Bolt, P. Duelli, BMNH.

Paratypes

Same data as holotype, 1 ³, 4 ♀. KYRGYZSTAN: Karakol Forest Station (N42.46 E78.52), 2030 m, 9 July 2016: 2 ³, 2 ♀, coll. same as holotype, NHMW; Alamüdün (N42.58 E74.48), 1900 m, 12 July 2016: 1 ³, 1 ♀, coll. same as holotype, BMNH. Larvae Ottuk , 2 first-instar, 2 second-instar, 5 third-instar, Karakol Forest Station 1 first-instar, 3 third-instar, Chychkan 2 second-instar, 2 third-instar, Alamüdün 1 first-instar, 2 second-instar, 1 thirdinstar, WFBM .

Etymology. Named in honour of Dr. Peter Duelli, the Neuroptera expert who discovered this new species – and many others – during his long and still active career.

Adult. Ground colour dark green, marked by pale yellow-white medial dorsal stripe running along rear of head and length of thorax and abdomen. Stipes entirely brown or black. Maxillary palp with apical segment yellowish, other segments marked dark brown dorsally. Gena with triangular black stripe, tapering towards the clypeus; remainder of gena yellowish-orange, turning red in diapause. Clypeus lateral edge often marked with blackbrown stripe, occasionally reddish but in diapause more clearly red. Frons marked by thin pink stripe leading from clypeogenal suture towards eye, ground colour entirely yellow. Scape, pedicel and postocciput unmarked. Pronotal setae mostly black, especially on the dark-green lateral margins, with conspicuously black bases; pale setae confined to the dorsal whitish-yellow median stripe. Nearly all setae on wing veins and legs are black. Pronotum marked with a green lateral band, becoming darker, in diapause almost black, toward the lateral edge. Metatarsal claw basal dilation ratio 2.75 – 3.43 (mean ± SD = 3.15 ± 0.25, N = 6). Forewing not tapered, apically symmetrical and rounded; length 13.00 – 13.90 mm in females (N = 8), 11.50 – 12.80 mm in males (N = 11); length:breadth ratio 2.96 – 3.39 (mean ± SD = 3.14 ± 0.11, N = 19). Forewing venation entirely green, except faint black markings on basal vein of intramedian (im) cell, the two Cu crossveins, and in some specimens the ends of the costal (C) and subcostal (Sc) crossveins; costal setae relatively short, inclined towards wing apex; basal Rs-M crossvein meets vein M at right angles and at apex of im cell. Abdominal segments 1 – 3 usually marked with a pair of brownish-black dorsal stripes flanking the pale medial stripe; in diapause, most abdominal segments similarly display these brownish-black stripes. Abdominal sternites clothed by black setae, except for some blond setae on proximal sternites; pleural membrane of second segment usually and of the first segment occasionally marked by a dark brown stripe; lip of sternite 8 + 9 in male broad and short (DE> FG, see fig. 5 in Henry et al. 2002) above a small chin (AB> BC). Tignum as in other carnea -group species.

Courtship song (25°C). (Note that all the following measurements are mean values.) Stereotyped substrate-borne vibrational signals produced by abdominal oscillations; nearly identical in males and females. Shortest repeated unit (SRU) multi-volleyed, made up of four distinct volley types, 5.5 s in total length. First volley of the SRU (type V1 ) 300 ms long, frequency decreasing from 102 to 72 Hz. Second volley (type V2 ) begins 330 ms after V1 ends, 816 ms long, frequency decreasing from 56 to 40 Hz. Third volley (type V3 ) more intense than any others, starting immediately after V2 ends, 346 ms long, same frequency characteristics as V1 . SRU ends with a series of 8 – 17 short ‘ terminal ’ volleys (fourth volley type), 180 ms long, volley period 306 ms, frequency decreasing from 77 Hz in the first terminal volley to 58 Hz in the last. Heterosexual duets consist of each individual repeatedly and politely answering single SRUs (multi-volley units) of its partner without overlapping.

Larvaı third-instar. Background of head, body and legs white. Dorsum of head with pair of relatively narrow pale- to medium-brown longitudinal, dorso-lateral stripes with darker spot mesad of the eyes, baso-lateral expansions extending towards eyes and pale to medium-brown lateral stripe of variable width immediately behind the eye; pale to medium-brown pigmentation mesad of eye, pale to very pale brown between pigmentation mesad of eye and dorso-lateral stripe, head surface sometimes (27% of larvae) exhibiting a small, pale fronto-medial spot. Pronotum with narrow, pale to mediumbrown, longitudinal dorso-lateral stripes; meso- and metanota with dorso-lateral spots, abdomen always unmarked. Coxa bearing two small, medium-brown spots laterally; distal femoral band and base of tibia pale brown.

Larvaı earlier instars. All markings on head, thorax and abdomen less sharply delineated but often more extensive than in third-instar (mature) individuals. Notably, head of the first instar is relatively dark. Femoral and tibial markings remain well defined or are often darker.

Life cycle and ecology. A habitat specialist, associated broadly with coniferous vegetation, at elevations greater than 1500 m. Number of generations per year unknown.

Stalked eggs oviposited singly rather than in groups. During winter diapause, adult retains green body colour but with some brownish-black striping.

Diagnosis/discussion. Chrysoperla duellii is a typical cryptic species of the Chrysoperla carnea -group, and as such is extremely difficult to distinguish morphologically from other members of the complex. It is also unexceptional and generally intermediate among the 20+ species of the carnea -group with respect to critical measurements of wing size and shape, width of the basal dilation of the pretarsal claw, and relative proportions of the ‘ lip ’ and ‘ chin ’ of the male abdominal terminus ( Henry et al. 2002). However, the adult of C. duellii is largely, though not absolutely, separable from its only known relatives in Kyrgyzstan, C. bolti and C. ‘ carnea-K, ’ by the consistent presence of a prominent dark stripe on the pleuron of the first (sometimes) and second (nearly always) abdominal segments; such ‘ lucasina stripes ’ are only occasionally present in C. bolti and C. ‘ carnea-K. ’ C. duellii is usually additionally separable from C. bolti by lacking C. bolti’ s two red spots on the frons, and from C. ‘ carnea-K ’ by having little or no black on any crossveins, more pink or red on the genae and clypeus, and the Rs-M crossvein meeting vein M exactly at the apex of the im cell. In overall adult morphology, C. duellii is more similar to C. bolti than it is to C. ‘ carnea-K ’ ( Henry et al. 2018, p. 1631).

Regarding the larva of C. duellii , its white background body colour is similar to North American C. calocedrii ( Henry et al. 2012) , but is distinctive among known Eurasian Chrysoperla larvae. The extensive pale brown pigmentation between the eye and dorso-lateral stripe is unique among species known to occur in Kyrgyzstan. The lack of red infusion on thoracic and abdominal segments will also differentiate C. duellii larvae from those of C. bolti . It is important to note that larvae of C. ‘ carnea-K ’ are not described.

Chrysoperla duellii sp. nov. can be most reliably separated from other species in the carnea -group by courtship song analysis – in fact, all species across the globe can unambiguously be assigned to species categories based on song phenotype, including the three that occur sympatrically in Kyrgyzstan. Whereas the song (SRU) of C . duellii is a long, complex signal consisting of four different volley types, that of C. bolti is short and simple, and that of C. ‘ carnea-K, ’ although equally as long as or longer than C. duellii’ s, includes only one rapidly repeating volley type ( Henry et al. 2018). Outside of Kyrgyzstan, the song of C . duellii is most easily mistaken for that of C. downesi in North America ( Henry 1980a). However , C . duellii has four volley types instead of the two types of C. downesi , and within-volley frequency modulation is always downward in C. duellii but upward in C. downesi ( Figure 1 (a,b)).

Distribution. Distributed across most of the Republic of Kyrgyzstan in central Asia, ≥ 1500 m.

Figures

Figure 1. Oscillographs (lower of each pair of traces) and sonographs (upper traces) of (a) a solo vibrational song (shortest repeated unit or SRU) of Chrysoperla duellii sp. nov. from Kyrgyzstan in central Asia and (b) a solo vibrational song of Chrysoperla downesi from northeastern North America, illustrating convergent song phenotypes in these two completely allopatric species. Each song was recorded at 25 ± 1°C and is drawn to the same timescale of 6.25 s. For C. duellii (a), each of the four distinctly different types of volleys characteristic of this species is labelled, while for C. downesi (b), each of its two distinctive volley types is noted. Within-volley vibrational frequency declines in each type of volley of C. duellii but increases in each type of volley of C. downesi – an important diagnostic (and plainly audible) difference between the two species.