Observations on the biology of Afrotropical Hesperiidae (Lepidoptera). Part 9. Hesperiinae incertae sedis: Zingiberales feeders, genera of unknown biology and an overview of the Hesperiinae incertae sedis
Cock, Matthew J. W.
Congdon, T. Colin E.
Collins, Steve C.
Zootaxa
2016
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3
201
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Discussion, Hesperiinae incertae sedis This paper completes our treatment of Hesperiinaeincertae sedis. We have treated this assembly of genera in five parts: dicotyledon feeders ( Cock & Congdon 2013), palm feeders ( Cock et al. 2013), grass and bamboo feeders (Cock & Congdon 2014), Dracaenafeeders (Cock et al.2015) and Zingiberalesfeeders (this paper). The 37 genera treated and their food plant families are summarised in Table 2, leaving only 11 genera for which nothing is known of the food plants or life history. TABLE 2. Summary of the genera of Hesperiinae incertaesedis and their food plant families. Genus (species) Evans’ Genera Group Food plant families1 Stages documented2 Ovum Caterpillar Pupa Acleros Acleros Fabaceae, Anacardiaceae, Malpighiaceae +++ +++ +++ Andronymus Acleros Fabaceae, Sapindaceae +++ +++ +++ Hypoleucis Acleros Costaceae +++ +++ Meza( sensu lato) Acleros Fabaceae, Linaceae, Dichapetalaceae + +++ Meza( sensu stricto) Acleros Poaceae Paronymus Acleros Dicotyledon ++ Gorgyra Ampittia Connaraceae Dichapetalaceae +++ +++ +++ Kedestes Ampittia Poaceae +++ +++ Prosopalpus Ampittia Poaceae +++ Astictopterus Astictopterus Poaceae +++ +++ Lepella Astictopterus Poaceae Tsitana Astictopterus Poaceae + + + ......continued on the next page TABLE 2.(Continued) Genus (species) Acada Ankola Evans’ Genera Group Ceratrichia Ceratrichia Food plant families1 Fabaceae Poaceae Stages documented2 Ovum Caterpillar +++ +++ Pupa +++ +++ Ceratrichia Osmodes Ceratrichia Ceratrichia Poaceae Marantaceae +++ +++ ++ +++ +++ Pardaleodes Parosmodes Rhabdomantis Teniorhinus Ceratrichia Ceratrichia Ceratrichia Ceratrichia Poaceae Combretaceae, Phyllanthaceae, Myrtaceae Marantaceae Fabaceae +++ +++ +++ +++ +++ Xanthodisca Xanthodisca astrape3 Fresna Melphinyet Ploetzia Ploetzia Gegenes Gegenes Zingiberaceae Marantaceae Fabaceae, Sapindaceae Euphorbiaceae +++ + + + +++ +++ + +++ Platylesches Erionota Artitropa Gegenes Plastingia Ploetzia Chrysobalanaceae Musaceae Asparagaceae +++ +++ + +++ +++ +++ +++ +++ +++ Caenides( dacela) Caenides( dacena) Chondrolepis Ploetzia Ploetzia Ploetzia Arecaceae Costaceae Poaceae ++ +++ +++ +++ +++ +++ +++ Gamia Gretna( balenge) Ploetzia Ploetzia Asparagaceae Arecaceae +++ +++ +++ +++ +++ Gretna( carmenetc.) Gretna( cylinda) Leona Moltena Ploetzia Ploetzia Ploetzia Ploetzia Arecaceae Marantaceae Arecaceae, Zingiberaceae Strelitziaceae ++ +++ +++ +++ +++ ++ +++ +++ +++ +++ +++ Monza Perrotia Ploetzia Ploetzia Poaceae Arecaceae, Poaceae +++ +++ +++ +++ Ploetzia Pteroteinon Semalea Zophopetes Ploetzia Ploetzia Ploetzia Ploetzia Arecaceae Arecaceae Zingiberaceae Arecaceae +++ +++ +++ +++ +++ +++ +++ +++ +++ +++ +++ Total in photographs 13 32 32 1 Families in bold were documented in our work, others are from the literature. 2 + from literature or museum specimens; ++ our observations; +++ photograph. 3 Asnoted above, T.B. Larsen (pers. comm. 2015) intended to create a new genus for this species. Evans (1937)placed it in Xanthodiscain Ceratrichiagroup, but its affinities are not clear. Ova. A priori, it seems likely that differences between ova are likely to be more conservative, than any observed amongst caterpillars or pupae, which are likely to show adaptations to avoid predation and parasitism and related to their food plants and leaf shelters (e.g. Greeney et al. 2012). However, this is not necessarily true as mortality of ova has been shown to be important in pest Lepidopterasuch as the polyphagous noctuid Helicoverpa armigera(Hübner), where egg predators play an important role in Kenya(Van den Berg et al.1999). MJWC noted that significant numbers of Artitropa erinnyis(Trimen)ova disappeared from a Dracaena steudneriplant in his garden in Nairobi (Cock et al. 2015). Hence, adaptations to maximise adhesion of ova to different typesof plant surfaces, or minimise the ability of predators such as ants to remove ova are certainly possible. We have images for only 14 genera ( Figure 41), but they do seem to indicate some groups within the incertae sedis. The genera Parosmodes, Semaleaand Platyleschesare united by have having wall-like ribs; further, the ova of Parosmodesand Semaleaare somewhat flattened compared to the relatively round ova of Platylesches, and the dorsal surface of the Parosmodesova is rugose. Hence, there are significant differences between these three genera as well as a striking similarity. There is a group of genera with rather similar ova: dome shaped, with fine ribs, including Erionota, Zophopetes, Pteroteinon, Leona, Artitropaand the dicotyledon feeding genera Aclerosand Andronymus. The similarity of the Asian Erionotaand the African Zophopetesand similar genera is striking. Gretna balengediffers in that the ribs are very fine and the egg shape is bun-shaped (an oblate spheroid). The two grass feeding genera, Astictopterusand Ceratrichiaare united by smooth dome-shaped ova, without apparent ribs. The bunshaped ovum of Gorgyraspp. differs from others, although this could be linked to its placement between leaves.
Caterpillars. The caterpillars of Hesperiinae incertae sedisdo not divide as easily into groups ( Figure 42). In general, the dicotyledon feeders have stouter caterpillars, and the grass feeders tend to have more slender caterpillars. The species currently placed in Gretnacan be grouped together because of the well-developed setae and white waxy powder on the head and body. Apart from this no clear groupings can be recognised, although Semaleaand Caenides dacenahave relatively narrow heads, Parosmodesand Melphinyethave distinct scale-like setae on the head (the similarities of the leaf shelters of these two genera have already been noted in Cock & Congdon (2013)), Acleros, Andronymusand tube shelter building Platylescheshave strongly contrasting pale markings on the head, and so on. Pupae. Representative pupae of the Hesperiinae incertae sedisare shown in Figure 43. None are of the Baorini type, which is perhaps slightly surprising since other tribes of Hesperiinaedo include genera with pupae of this type( Cock & Congdon 2012). Possible groupings based on the pupae are not that obvious. Gorgyraand Pteroteinonspp. have a bifurcate frontal projection, Leonahas a blunt frontal projection, Chondrolepishas a short down-turned frontal projection, Semaleaand to a lesser degree Xanthodiscahave a small frontal protuberance and the other genera have none; this does not seem to be a helpful character. We have noted above that the three species of Gretnawhich are doubtfully congeneric have quite similar caterpillars, but the pupae are very different, implying they belong in three different genera, none of which show much affinity to any other genera. The frontal projection of the pupa of G. balengeis unique, and the tufted pupa of G. cylindais also very distinctive, but this may reflect that it is the only Afrotropical species that we have documented to form its pupa on the food plant leaf without the construction of any shelter. Aspreviously noted the pupae and pupal shelters of Parosmodesand Melphinyetshow affinities ( Cock & Congdon 2013), and the pupae of at least some Platyleschesspp. are generally similar. The pupae of Aclerosand Andronymusshow affinities in shape and colouring as well as pupal shelter construction. Above, we have noted that the pupae of Caenides(both the palm-feeding C. dacelaand the Costaceae-feeding C. dacena), Semalea, Xanthodiscus, and Hypoleucisare united by the broad C-shaped rim to the T1 spiracle. The pupae of Gorgyraand Osmodesdo not show any obvious affinities to any other genera. The pupae of Zophopetes, Moltena, Monzaand Perrotiaare similar in shape and colour, while those of Gamia, Artitropa, and Erionotaare similar but paler. Chondrolepis, Pteroteinonand Leonaare also quite similar to this group, but have a frontal projection and the cremaster of Chondrolepisis less developed and may not be functional, although this may be a reflection of a tightly rolled pupal chamber obviating the need for pupal attachment. The dicotyledon-feeding Mezaspp. may also relate to this group, but their exposed pupation site is perhaps linked to the unusual dorsal markings. The simple pupa of Acada, which could easily be mistaken for that of a member of the Noctuoidea, might also belong with this group. The pupae of Pardaleodesand Ankolaare of similar shape and both are very flimsy (Cock & Congdon 2014), but their shape suggests they may have affinities with this group. There may also be affinities with Kedestes. In summary, based on the pupae alone, we have nine possible groups: 1 Parosmodes, Melphinyetand perhaps Platylesches 2 Aclerosand Andronymus 3 Caenides dacela, Semalea, Xanthodiscus, and Hypoleucis4 Zophopetes, Moltena, Monza, Perrotia, Gamia, Artitropa, and Erionotawith possible subgroups or related groups (a) Pteroteinonand Leona, (b) Chondrolepis, (c) dicotyledon-feeding Meza,(d) Acada, (d) Pardaleodesand Ankolaand (e) Kedestes 5 Gorgyra 6 Osmodes 7 Gretna carmen8 Gretna balenge9 Gretna cylinda These are not incompatible with the tentative groupings suggested for the limited observations of ova. The weak groupings suggested for caterpillars are also mostly compatible except that the similarities of the caterpillars of the three species of Gretnasuggest that they are more closely related than do the very dissimilar pupae. We look forward to seeing if and how these groups may align with future development of the classification of Hesperiinae incertae sedisbased on the T.B. Larsen’s work on male genitalia and adult characters (mostly unpublished at present) and future expansion of the recent molecular and adult character analysis ( Warren et al. 2009). In doing so, we recognise that any classification based on the early stages (and hitherto we are only considering a morphological classification rather than a phylogeny) will not necessarily align with classifications or phylogenies based on the adults, but analyses based on both combined are likely to yield a more robust phylogeny ( Meier & Lim 2009). For example, Penz et al. (2013)showed that a phylogeny based on early stages of Brassolini (Nymphalidae)was less well resolved than one based on adult characters, but that the phylogeny based on the combined dataset was similar, but not identical to that based on adult characters only. On the other hand, caterpillars and pupae living in an exposed way (as Brassolinido) are likely to be subjected to stronger and perhaps more convergent natural selection, compared to those of Hesperiidae, which mostly live in shelters. We have already commented on the similarity of the early stages of diverse Hesperiinaethat feed partially exposed, particularly on grasses and other monocotyledons. The caterpillars mostly have green bodies with longitudinal lines, and the pupae have similar colouring and a pointed frontal spike, which we have referred to as Baorini typepupae (Cock & Congdon 2014). At the time we hesitated to suggest whether this was a conservative character or the result of convergent evolution to address a common problem; today we are more inclined to the later explanation. We have noted another example of convergent evolution that will obscure relationships between genera in this series of papers: the development of ‘counterfeit predator eyes’ on the heads of caterpillars and pupae which live in shelters and should gain some advantage by frightening small vertebrate predators ( Janzen et al. 2010). Thus natural selection will obscure phylogeny where selection acts to converge on particular models for life style reasons.