Hemileuca maia menyanthevora Pavulaan, 2020

Pavulaan, Harry, 2020, A phenotypic comparison of regional populations of Hemileuca maia (Drury, 1773) with designations of new subspecies (Bombycoidea, Saturniidae, Hemileucinae)., The Taxonomic Report of the International Lepidoptera Survey 8 (5), pp. 1-17 : 8-9

Hemileuca maia menyanthevora Pavulaan, 2020 New Subspecies

Bogbean Buckmoth

ZooBank registration: urn:1sid:zoobank.org:act: B7D0030D-1C45-4733-A1CE-79B6515AC4E1

This taxon ( Figs. 9 , 10 & 15) represents a small grouping of wetland-associated populations in northern New York State, around Ottawa, Ontario and in southeastern Wisconsin. Rubinoff & Sperling (2004) found no marked genetic divergence from H. maia populations nearby in New York State, lending to its status as a recent postglacial taxon. Long considered to be a unique ecological form of H. maia , adapted to use of a particular hostplant ( Menyanthes trifoliata ), but the lack of an adequate description and naming hinders conservation efforts. In the absence of formal description, and to further conservation efforts in New York and Ontario, the Evolutionary Significant Unit (ESU) concept was employed. Fraser & Bernatchez (2001) define the ESU concept as: Segments of species whose divergence can be measured or evaluated by putting differential emphasis on the role of evolutionary forces at varied temporal scales [within a species].

The present paper resolves at least one issue, that of formal description and naming. One of the most difficult hindrances to the study of this taxon is locating any specimens able to serve as types. Only the McGuire Center for Lepidoptera and Biodiversity had institutional specimens, which serve as the holotype and paratypes. Ross Layberry provided information on specimens collected in Ontario in 1984 (pre-act). Additional analysis of New York, Wisconsin, and Ontario phenotypes came from many internet resources and published works ( Handfield, 2011). It is not clear whether the New York, Wisconsin and Ontario populations all represent the same exact taxon. COSEWIC (2009) states that genetic exchange between U.S. and Canadian populations does not occur due to distance between population groupings. Further research is warranted. This may actually represent a full species. The Bogbean Buckmoth was granted state protection as threatened in 1999 in New York State, though it has not been formally described or named. It is also protected as endangered in Canada as of 2009, and also in Ontario under the Endangered Species Act , 2007.

Common name Bogbean Buckmoth ( Hemileuca sp. 1 ) per New York Natural Heritage Program (2020) and NatureServe Explorer (2020).

Type locality: Holotype (male): Sep. 22, 1985. Brennan Beach Camp , Pulaski, Oswego Co., N.Y. Leg. P. Savage . Allotype (female), 9 male paratypes and 4 female paratypes, same data as holotype . All specimens deposited in the McGuire Center for Lepidoptera & Biodiversity, Gainesville, FL.

Range: Confined to six known fens in Oswego County, N.Y. and in four fens near Ottawa , Ontario ( Fig. 16 ). Kruse (1998) provides detailed information on two sites in Marquette and Ozaukee Counties in Wisconsin.

Habitat: Described as minerotropic [stream or spring-fed] fens at the east edge of Lake Ontario and open graminoid fens (New York Natural Heritage Program, 2020); open, low-shrub fens (Government of Canada Species Profile, 2020), and open, calcareous, graminoid and low shrub fens in Ontario (COSEWIC, 2009). COSEWIC (2009) gives the habitat description of the two groupings of New York as: (1) a complex of several discrete, rich, shrub-dominated fen openings behind barrier dunes on Lake Ontario at one site, and (2) an inland complex of edge-dominated floating peat mats on lake edges. This subspecies (or species) is extremely vulnerable to extirpation in New York, because its habitat is rapidly degrading and is significantly threatened (New York Natural Heritage Program, 2020). Habitat threats include succession by invasive Typha angustifolia (Narrowleaf Cattail) , Phragmites australis (Common Reed) , Lythrum salicaria (Purple Loosestrife) , and Frangula alnus (Glossy Buckthorn) ; hydrologic alteration resulting in lowering of the Lake Ontario water level; nutrient pollution run-off from surrounding areas; surface flooding at two fen sites; and parasitoid wasps and other predators. Pesticide application in the habitat could be disastrous. In Ontario, there are nearly identical threats to the habitat (COSEWIC, 2009).

Flight period: Sept. 9 to Oct. 12.

Hosts: A rather complicated series of choices (COSEWIC, 2009; Government of Canada Species Profile, 2020) across a broad range of suitable hostplants. In Ontario, females were observed depositing egg rings mostly on Myrica gale (Sweet Gale) , Betula pumila (Bog Birch) , but also other low shrubs such as Spiraea alba (Narrow-leaved Meadowsweet), Salix petiolaris (Slender Willow) , Salix bebbiana (Bebb s Willow) and odd choices such as Phragmites australis (Common Reed) , Muhlenbergia glomerata (Marsh Muhly) , Solidago (Goldenrod sp.), Aster ( Aster sp. ), and Scirpus (Rush sp.) [The primary host Menyanthes trifoliata has already dried by the time females are looking to oviposit]. Many of these plants are unsuitable for larval development. Newly-hatched larvae in the following year seek out Vaccinium macrocarpon (Bog Cranberry) , later switching to M. trifoliata as it leafs out. Late instars disperse widely, being found on B. pumila , S. petiolaris , S. bebbiana , Salix pedicellaris (Bog Willow) , and Spiraea alba (Narrow-leaved Meadowsweet).

In a New York study ( Pryor, 1998), similar observations were obtained of ovipositions on M. gale , Acer rubrum (Red Maple) , Woodwardia (= Anchistea ) virginica (Virginia Chain Fern), Alnus incana rugosa (Speckled Alder), Carex (Sedge sp.), Chamaedaphne calyculata (Leatherleaf) , Salix pedicellaris (Bog Willow) , S. alba , and Cornus sericea (= stolonifera) (Red Osier Dogwood). Likewise, many of these plants are unsuitable for larval development. Larvae have been observed leaving unsuitable plants and seeking out V. macrocarpon and later switching to M. trifoliata as it leafs out. Larvae were further found throughout summer feeding on: A. incana rugosa , Aronia melanocarpa (Black Chokeberry) , Carex (Sedge sp.), C. calyculata , Ilex verticillata (Common Winterberry) , M. trifoliata , Quercus (Oak sp.), S. pedicellaris , S. alba , and V. macrocarpon . [The name Buckbean Buckmoth might thus be a misnomer.]

Description: FW length: males 22-32 mm; females 26-36 mm. [Holotype (male) FW length is 27.6 mm.] Despite published claims, this subspecies is very distinct and nearly identical to H. lucina . Larger than ssp. maia . Wings light gray and highly translucent, with the cream-tinted median bands nearly transparent [text can easily be read through the wings when placed against the wings]. The median bands on both sets of wings are much wider than in all other maia subspecies, generally completely enclosing the forewing median discal streak and covering about 1/3 of the interior of the wings. The basal third of the forewings are darker than the outer third. Female wings are not as broad as the other maia subspecies, the wings are more rounded and posess a dark gray wing margin on both sets of wings. The median band pattern in females is remarkably similar to H. nevadensis females.

This subspecies is the most unique of all the maia -complex populations and likely represents a different species-level taxon. It appears to be nearly identical in morphology to H. lucina . Handfield (2011) describes it as Hemileuca sp. near lucina due to great similarity to H. lucina . Legge et al. (1996) suggest this taxon is an evolutionarily significant unit, possibly a separate species. Crandall et al. (2000) consider this an evolutionarily significant unit (ESU), based on ecological and genetic data, and further suggest that these are more relevant for conservation efforts. They consider the evolutionary heritage of ESU s based on ecology will better foster conservation management. Buckner et al. (2014) state that Bog Buckmoth populations are not consistently distinguishable from other H. maia populations on the basis of any diagnostic set of color or other morphological characters. This paper presents a different conclusion.

Figures

Fig. 9. Hemileuca maia menyanthevora Pavulaan, 2020. Holotype. Sep. 22, 1985. Brennan Beach Camp, Pulaski, Oswego Co., N.Y. Leg. P. Savage. Male. Dorsal view.

Fig. 16. Documented range of Hemileuca maia Drury (1773) and subspecies.