Podalonia canescens (Dahlbom 1843) - African Silver-pubescent Cutworm Wasp

Gaster black and reddish. Legs, petiole and clypeus black. Petiole a little longer than hindtarsomere I. Clypeus and frons with appressed silver setae ('canescens' = with white/gray pubescence). Median lobe of clypeus slightly produced. Erect setae on head and thorax whitish. Scutum coarsely punctate, punctures at least one diameter apart. Wings almost clear, at most slightly yellowish. 14-20 mm.

Species diagnosis from Dollfuss 2010:
https://www.zobodat.at/pdf/LBB_0042_2_1241-1291.pdf
Podalonia canescens has a propodeal enclosure with erect setae, the gaster is red basally and the clypeus and frons are covered with appressed silver setae.
The female of this species differs from P. hirsuta [not Afrotropical] in having distinct arolia. In addition, it differs from the similar species P. tydei [also recorded from Afrotropical region] and the European species P. luffii in having a petiole that is longer than hindtarsomere I. In addition, P. canescens differs from the African species P. erythropus [only known from Cameroon] in having black legs, a black petiole and a black clypeus. The female of P. canescens differs from the African species P. sheffieldi [known from Malawi and Tanzania] in having whitish erect setae on the head and thorax.
The male has a broadly produced clypeus with a free margin that is slightly concave. It differs from the male of P. tydei in having a more produced clypeus, a coarsely and densely punctate scutum nearly without appressed silver setae, a mesopleuron only with sparse appressed silver setae, and terga I and II of gaster with dark spots.

Distribution: Central, East and Southern Africa
Type locality: Western Cape Province: Cape Town area (Lund).

Biology: Podalonia canescens digs a simple one-celled nest; cell provisioned with a single hairless caterpillar of the cutworm type (Noctuidae).
Gess, F. 1981 (https://www.biodiversitylibrary.org/page/51757872#page/19/mode/1up) describes the biology based on observations from South Africa, Hilton Farm 18 km west-northwest of Makhanda): nesting in friable soils, method of nest digging, wing vibrating during nest excavation, hunting precedes nest excavation.

Pollination by sexual deception:
Although pollination by sexual deception is widespread amongst orchid species it has been recorded only in 1994 for orchids in South Africa by Steiner, K. E., Whitehead, V. B., & Johnson, S. D. (Floral and Pollinator Divergence in Two Sexually Deceptive South African Orchids. American Journal of Botany, 81(2), 185. doi:10.2307/2445632 https://sci-hub.st/https://doi.org/10.2307/2445632) who studied two Disa species in the Western Cape to evaluate the effect that minor differences in floral color, shape, and scent have on pollination.
Observations at several sites indicated that Disa atricapilla is pollinated almost exclusively by male Podalonia canescens. The wasp was found to exhibit mate-seeking behavior when approaching and visiting flowers. This together with the absence of a floral reward suggests that this orchid is pollinated through sexual deception.
D. atricapilla is fragrant and the scent is produced mainly by the petals. The flowers of this species absorb ultraviolet light strongly and the back of the sepal is shiny in the visible and ultraviolet ranges, which is thought to mimic the shine from a pair of folded wasp wings.
The visitation behavior is described in the study: "Podalonia canescens males exhibited typical mate-seeking behavior when visiting Disa atricapilla flowers. This consisted of patrolling plants repeatedly and in many cases inspecting inflorescences by hovering or circling briefly without landing. In other cases, wasps landed in the center of an inflorescence and looked around very briefly before flying off (<2 seconds), and in still other cases the wasps stayed on the inflorescence long enough (<5 seconds) to move from the center of the inflorescence out toward the tip of an open flower. When this occurred, they would probe the point where the two petals come together over the anthers (the site of maximum scent production). Although probing visits were rarely observed, such behavior would have been necessary in order to bring wasps into contact with the pollinaria. The large number of pollinaria carried by some individuals suggests that this type of behavior was much more frequent than observed, while the constancy of this visitation behavior can be inferred from pollinarium placement on the ventral surfaces of the wasps".

iNat observation:
Male with pollinaria attached https://www.inaturalist.org/observations/205526940

Publicerat 26 april 2024 08.01 av traianbertau