Belonopterygini

Italochrysa italica, copyright Nigel Jones.

Belongs within: Chrysopidae.

The Belonopterygini are a group of relatively robust green lacewings whose larvae are associated with ant nests (Freitas & Penny 2001).

Of lions and lace
Published 7 July 2008
The “non-green, green lacewing” (Catanach, 2007) Abachrysa eureka. Photo by M. C. Thomas.

There is a term that bird-spotters use to describe the ability to recognise what species a bird belongs to even if one cannot see the details of its features—they refer to the “jizz” of a bird, derived from the acronym GIS for “general impression and shape”. The jizz of a bird species is not something that can be described easily, if at all—it is something that can really only be appreciated with experience. It should hardly come as a surprise that the same concept applies with identifying other organisms just as much as birds. Lacewings (Neuroptera) are a smallish order of insects (only about 5000 species) that include a diversity of forms, but many look at first glance not unlike small dragonflies. Still, a closer look will reveal significant differences to a dragonfly. For a start, lacewings have longer antennae and are able to fold their wings back over their abdomen in a way that no dragonfly can. There is also the feature that gives them their name—the wings of lacewings are particularly densely covered with veins, the little criss-crossing fluid-carrying lines that you can see on any insect wing. While you might need to look very closely indeed to see the individual veins, the cumulative effect of the dense veins is to give lacewing wings a distinctive shimmer, like light off satin, or the glimmer of colour across oil. This page’s subject is a specific group of lacewings—the tribe Belonopterygini.

Lacewings have a complete metamorphosis, meaning they have a distinct larval stage separated by a dormant pupal stage from a very different-looking adult. Most lacewings start out life as formidable predators, and are quite recognisable by their large, protruding jaws. The most famous are the antlions of the family Myrmeleontidae, which dig themselves conical pits at the bottom of which they lie dug into the soil, waiting for any small insects unlucky enough to fall into the pit. While the large jaws are used for capturing and macerating prey, lacewing larvae are actually liquid feeders, injecting digestive saliva into their prey then sucking out the dissolved juices (Canard 2007). One intriguing (yet kind of disgusting) feature of the order is that the midgut is not actually connected to the hindgut until pupation, meaning that the larva is not capable of defecation. Any indigestible waste products are stored in the gut until the lacewing reaches adulthood and passed after emerging from the pupa. Can you imagine the relief?

The belonopterygin Italochrysa insignis. This photo illustrates very well the distinctive shimmer that neuropteran wings possess in the right light and which I’ve found is actually one of the quickest ways to recognise an adult lacewing. Photo by Sheila.

Belonopterygini are a cosmopolitan tribe of a different family, the Chrysopidae (green lacewings), whose larvae are active hunters, many of them of economic significance as predators of plant pests such as aphids and thrips. Belonopterygin larvae are specialist associates of ant nests (Freitas & Penny 2001), feeding on the ants therein. Unfortunately, such specialist habits make Belonopterygini one of the less-studied chrysopid groups, and I have been unable to find how the larvae evade detection by the ants. Like other chrysopids, belonopterygin larvae use small bits of soil and debris to disguise themselves, starting with the shell of the egg they hatched from (Catanach, 2007). Larvae of other chrysopids have been observed to incorporate the husks of drained prey into their trashy disguises so I would be interested to know if belonopterygins do the same.

Adult chrysopids may be predacious like the larvae, or they may feed on non-live food such as honeydew. Honeydew-feeding species possess diverticula in the gut that house symbiotic yeasts aiding the lacewing in digestion. Sounds produced by tapping the abdomen on the substrate are used by chrysopids in courtship, and the pattern of sounds produced may differ significantly between closely related species (New 1991). Eggs are laid perched on the end of long silk threads.

The red-lined wings of South America
Published 1 August 2011

So far as I’ve been able to find, what you see above is the only published illustration of the South American lacewing Belonopteryx arteriosa, from its original description by Gerstaecker (1863) (or very nearly from there: somewhat confusingly, the plate illustrating this animal was published an issue earlier than the article describing it). It is something of a pity that the drawing is not in colour as Gerstaecker’s description indicates a quite handsome animal: about 16 mm long with a ca 20 mm wingspan* with a mostly orange head, golden yellow body and blood red veins on the wings. The first segment of the antenna was yellow, the second darker, and the remainder black. Along the medial and secondary radial veins, the red colour of the veins extended to part of the cells on either side, producing two longitudinal red stripes on each wing.

*Gerstaecker gives the body length as 8 lines, with the front wings 9.5 lines long. A ‘line’ is a unit of measurement used by a number of 18th and 19th century biologists. The exact length of a line seems to have varied somewhat between countries (see this page for explanations), though it seems to have generally been a little more than 2 mm. Linnaeus apparently defined a line in the introduction to Philosophia Botanica as the length of a lunule (the white half-moon at the base of a fingernail) on any finger other than the thumb.

Despite being the type of the tribe Belonopterygini, Belonopteryx arteriosa seems to have received little attention since its description. Gerstaecker (1863) held only a single female specimen, reporting its collection locality (with a precision not uncommon for his time) as “Brazil”. Freitas & Penny (2001) indicated that this species was known only from three specimens from Argentina (whether this indicates that Gerstaecker’s locality was mistaken, or whether this is in addition to the original location, I couldn’t say). The larva of B. arteriosa has never been identified, though larvae of related genera are associated with ant nests.

Systematics of Belonopterygini

Characters (from Freitas & Penny 2001): Adults thick-bodied with prothorax wider than long; antennomeres wider than long beyond the first few basal segments. Larvae associated with ant nests.

<==Belonopterygini
    |--BelonopteryxFP01
    |--AbachrysaFP01
    |--Nacarina Navás 1915FP01
    |    |--N. aculeata de Freitas & Penny 2001FP01
    |    |--N. cordilleraFP01
    |    |--N. gladius de Freitas & Penny 2001FP01
    |    |--N. lavrasana de Freitas & Penny 2001FP01
    |    |--N. panchlora (Gerstaecker 1888)FP01
    |    |--N. plectorica (Navás 1919)FP01
    |    |--N. sagitta de Freitas & Penny 2001FP01
    |    `--N. wagneri Navás 1924FP01
    `--Italochrysa Principi 1946FP01, N80
         |--*I. italica [=Hemerobius italicus]N80
         |--I. banksi New 1980N80
         |--I. chloromelas (Girard 1862) [=Hemerobius chloromelas]N80
         |--I. facialis (Banks 1910) [=Nothochrysa facialis]N80
         |--I. froggatti (Esben-Petersen 1914) [=Nothochrysa froggatti]N80
         |--I. insignis (Walker 1853) (see below for synonymy)N80
         |--I. lata (Banks 1910) [=Nothochrysa lata]N80
         |--I. luddemanni (Navás 1935) [=Nothochrysa luddemanni]N80
         |--I. nigrinervis (Esben-Petersen 1917)[=Nothochrysa nigrinervis]N80
         `--I. punctistigma (Esben-Petersen 1918) [=Nothochrysa punctistigma]N80

Italochrysa insignis (Walker 1853) [=Chrysopa insignis; incl. Nothochrysa insignita Navas 1913, C. stictoneura Gerstaecker 1885, N. xanthocephala Navas 1932]N80

*Type species of generic name indicated

References

Canard, M. 2007. Natural food and feeding habits of lacewings. In: McEwen, P., T. R. New & A. Whittington (eds) Lacewings in the Crop Environment pp. 116–129. Cambridge University Press.

Catanach, T. A. 2007. Abachrysa eureka (Banks) (Neuroptera: Chrysopidae): egg, first instar larva and biological notes. Unpublished thesis, Texas A & M University.

[FP01] Freitas, S. de, & N. D. Penny. 2001. The green lacewings (Neuroptera: Chrysopidae) of Brazilian agro-ecosystems. Proceedings of the California Academy of Sciences 52: 245–395.

Gerstaecker, A. 1863. Ueber einige neue Planipennien aus den familien der Hemerobiiden und Panorpiden. Entomologische Zeitung 24 (4–6): 168–188 (plate in issue 1–3).

[N80] New, T. R. 1980. A revision of the Australian Chrysopidae (Insecta: Neuroptera). Australian Journal of Zoology, Supplementary Series 77: 1–143.

New, T. R. 1991. Neuroptera. In: CSIRO. The Insects of Australia 2nd ed. vol. 1 pp. 525–542. Melbourne University Press.

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