FNZ 12 - Pompilidae (Insecta: Hymenoptera) - Mimicry
Harris, AC 1987. Pompilidae (Insecta: Hymenoptera). Fauna of New Zealand 12, 160 pages.
( ISSN 0111-5383 (print), ; no. 12. ISBN 0-477-02501-3 (print), ). Published 13 Nov 1987
The endemic Pompilidae throughout New Zealand are included in three well established mimicry associations, each having Mūllerian and Batesian components. Female pompilids, ichneumonids, and other stinging insects comprise the Mūllerian component, while male pompilids and icheumonids together with sun-loving beetles and flies are Batesian mimics. Male pompilids will sometimes mimic females of another, more common, species. Mimicry in the colour-variable species is selectively less important than variable melanism. Thus, female pompilids switch from a red-and-gold complex to a black-and-yellow one south of latitude 45°S, where reduced insolation and temperature evidently induce the melanism that confers thermal advantage.
Mimicry complex 1: black body and clear wings
COLORATION. Body, legs, antennae, and palpi shining black; wings clear hyaline, or very lightly clouded.
MOVEMENTS. Heliotaxis, and walking in a characteristic jerky manner interspersed with short bursts of flight.
MūLLERIAN COMPONENT. Females of Priocnemis (Trichocurgus) nitidiventris, P. (T.) ordishi n.sp., P. (T.) carbonarius, and P. (T.) crawi n.sp. (Pompilidae); also various endemic solitary bees, sphecids, and Ichneumonidae.
BATESIAN COMPONENT. Males of the above four species, Priocnemis (T.) monachus (males only), various Diptera such as Pollenia pernix (Hutton) (Calliphoridae), and elaterids.
REMARKS. This complex favours more open places than the other mimicry associations. Its pompilid elements do not show colour variation.
Mimicry complex 2: red body, yellow thorax, and amber wings
COLORATION.Body bright red except for hind part of thorax, propodeum, and sometimes part of first segment of metasoma, which are glistening yellow; wings tinted with amber; legs red; antennae black.
CHARACTERISTIC MOVEMENTS. Heliotaxis (appearing almost exclusively in sunlight, and disappearing very rapidly when the sunlight fades). Walking in a bold, jerky manner, with the antennae held out in front, constantly moving, sometimes palpating the ground (some dipterous mimics compensate for their short antennae by having the first pair of legs black but the other two pairs red, and waving the front legs about like antennae). Taking short flights interspersed with periods of jerky walking.
MūLLERIAN MIMICRY ASSOCIATES. Ichneumonidae (females) - Aucklandella utetes, A. thyellma, A. conspirator, A. sp. A, A. sp. B, Levansa decoratoria, L. leodacus, L. sp. A, Degithina davidi, D. exhilarata, D. hersilia, D. sp.A, D. sp. B; Pompilidae (females) - Sphictostethus nitidus, S. calvus, S. fugax, Priocnemis (T.) conformis.
BATESIAN MIMICS. Ichneumonidae (males of above species); Pompilidae (males of above species); Proctotrupidae - Proctotrupes maculipennis; Tipulidae - Gynoplistia cupreapercara; Stratiomyiidae - Benhamyia apicalis; Asilidae - Saropogon antipodus, S. extenuatus; Cleridae - Phymatophaea ignea; Elateridae - Sphaenelater lineicollis; Cerambycidae - Gastrosaris nigrocollis.
REMARKS. The asilids function as Batesian mimics with respect to avian predation, and as aggressive mimics towards male ichneumonids and pompilids, which sometimes appear to mistake the asilids for females of their own species and fly towards them, when they are eaten. Proctotrupes maculipennis is a specific mimic of Sphictostethus calvus. The wing coloration, forewing fascia, and apical wing infuscation are strikingly similar, and the body changes from red to black southwards in a notably similar way. Both Sphictostethus fugax and Priocnemis (T.) conformis are models for Saropogon extenuatus.
Mimicry complex 3: black body, yellow abdominal base, amber wings
COLORATION. Head and thorax black; base of abdomen bright orange-yellow; apex of abdomen black; wings tinted with amber, their apices lightly infuscated; coxae and apical parts of tarsi black. (Abdomen always smooth, shining, and devoid of bristles, even in the tachinid mimic Huttonobasseria verecunda Hutton.)
CHARACTERISTIC MOVEMENTS. As for the previous mimicry complex.
MūLLERIAN MIMICRY ASSOCIATES. Ichneumonidae (females) - Aucklandella geiri, A. sp. A, A. sp. B, Degithina decepta, D. sp. A, D. sp. B, D. sp. C; Pompilidae (females) (below latitude 43° 30'S) - Sphictostethus fugax, S. calvus, Priocnemis (T.) conformis, Epipompilus insularis.
BATESIAN MIMICS. Ichneumonidae - males of species listed above; Pompilidae - males of species listed above; Proctotrupidae (below latitude 43°30'S) - Proctotrupes maculipennis; Stratiomyidae - Benhamyia straznitskii; Tachinidae - Huttonobasseria verecunda.
AGGRESSIVE MIMIC. Saropogon extenuatus (Asilidae) is an excellent mimic of melanic Priocnemis (T.) conformis females, to which male pompilids are sometimes attracted, whereupon the asilid captures them.
REMARKS. Both Mūllerian and Batesian components appear to be based on Degithina decepta females. This complex gains species south of latitude 44°S.
Effects of thermal melanism on mimicry
South of about latitude 44°30'S mimicry complex 2, dominant in northern districts, fades out and mimicry complex 3 gains new associates. This is especially true of species that are strongly subject to thermal melanism, such as Priocnemis (T.) conformis, Sphictostethus fugax, and S. calvus (Pompilidae), several Degithina, Levansa, and Aucklandella species (Ichneumonidae), Proctotrupes maculipennis (Proctotrupidae), Benhamyia straznitskii (Stratiomyidae), Gastrosarus nigrocollis (Cerambycidae), and others, which become completely black-bodied and switch to the association with black body, yellow thorax, and amber wings. Several species (such as Sphictostethus calvus and Priocnemis (T.) conformis) have the body completely black, i.e., without orange-yellow on the propodeum and the base of the abdomen. The pompilids, however, hold the wings tightly over the back, so that the amber basal part resembles the orange base of the abdomen and the enlarged apical infuscation corresponds to the black abdominal apex. On Stewart Island some Priocnemis (T.) conformis males have the wings entirely infuscated, and the body and appendages are black as well. These resemble members of the black-bodied, clear-winged mimicry complex when running on the ground.