Polyphyly of Lichen-cryptic Dagger Moths: synonymy of Agriopodes Hampson and description of a new basal acronictine genus, Chloronycta, gen. n. (Lepidoptera, Noctuidae)
Author
Schmidt, B. Christian
Author
Wagner, David L.
Author
Zacharczenko, Brigette V.
Author
Zahiri, Reza
Author
Anweiler, Gary G.
text
ZooKeys
2014
421
115
137
http://dx.doi.org/10.3897/zookeys.421.7424
journal article
http://dx.doi.org/10.3897/zookeys.421.7424
1313-2970-421-115
B69FD062806F4AE78C681F8FD650D2A7
B69FD062806F4AE78C681F8FD650D2A7
Taxon classification Animalia Lepidoptera Noctuidae
Acronicta fallax
comb. n.
Figs 2, 5, 9, 13
Adult morphology.
The fate of the genus
Agriopodes
is anchored to the phylogenetic position of
Acronicta fallax
, its type-species. Comparison of genitalic structure of
Acronicta fallax
to all North American and most Eurasian
Acronictinae
species reveals that genitalic features are most consistent with those found across an endemic North American group of
Acronicta
species, consisting of
Acronicta tritona
,
Acronicta grisea
,
Acronicta falcula
(Grote),
Acronicta lithospila
Grote,
Acronicta hamamelis
Guenee
,
Acronicta mansueta
Smith,
Acronicta paralella
(Grote) and
Acronicta vinnula
, here termed the tritona-group. Structural synapomorphies for these species are primarily those of the male genitalia (Fig. 5), including a short, claw-like clasper and a broad shield-like juxta (wider than long), with strap-like dorso-lateral extensions. The male vesica structure is moderately complex and consists of a sausage-shaped main chamber that curves ventrally then right laterally, which is armed with short, spade- to thorn-like spines to longer attenuated spines. The size and position of the vesica diverticula are unique, with thumb-like diverticula consistently present in the basal and sub-basal positions, and smaller diverticula variably present in the medial and apical positions. In females, the corpus bursae is relatively broad and rounded, shaped like a heart or a boxing glove with the appendix bursae forming the
'thumb'
(Fig. 9). Females of the tritona-group (Figs 10, 11) lack the dense, persistent patch of fine, felt-like hairs between the 8th tergite and sternite that is present in the
Acronicta hasta
-group. The hasta-group contains at least 14 species, largely corresponding to "Group II" of
Forbes (1954)
. As also suggested by the placement of
Acronicta superans
in our tree (Fig. 1), the hasta-group is related to the tritona-group, but exhibits a number of distinctive autapomorphies not present in either the tritona-group or
Acronicta fallax
, such as a unique hourglass-shaped juxta; modification of the quadrate ventral process of the clasper into a broad, scoop-like flange and a dorsally curved pollex; and as noted above, a patch of persistent felt-like setae on the female A8 pleuron.
Structurally,
Acronicta
fallax
shows clear affinities to
Acronicta grisea
and
Acronicta falcula
of the tritona-group; the valve, clasper and uncus are much like those of
Acronicta grisea
, with the clasper apex slightly less curved. The dorsolateral straps of the juxta are spinulose, and the medioventral portion of the juxta is produced into a rounded knob that is unique to
Acronicta fallax
, although
Acronicta tritona
shows a rudimentary form of this. Aedeagus and vesica structure of
Acronicta fallax
are also similar to those of
Acronicta grisea
and
Acronicta falcula
, with two basal, unarmed diverticuli, a spinose main chamber, and a finely spinulose distal portion of the main chamber. The large spine field is composed of short, broad-based spines basally, and rounded, spade-like spines distally, similar to those found in
Acronicta tritona
. The female genitalic structure of
Acronicta fallax
is most similar to
Acronicta grisea
(Fig. 10). Larval morphology does not offer support for a special association among
Acronicta fallax
and tritona / falcula / grisea, although there is greater similarity of fallax to the tritona group than to larvae of the hasta-group.
Many
Acronicta
species bear a prominent black basal, anal and apical forewing dash; the basal and anal dashes are sometimes transected by a crescentic line resulting in a dagger-like mark (hence the common name dagger moths). These forewing dashes typical of
Acronicta
are also present in modified form in
Acronicta fallax
, with the apical and anal dash (dagger marks) broadly joined to the postmedial line to form two roughly triangular postmedial patches. The basal dash is short and thick; and there is a black rectangular bar connecting the orbicular and reniform spots; the orbicular and reniform spots are occasionally and then only incompletely outlined. Unlike the green psaphidines (
Amphipyrinae
,
Psaphidini
:
Feralia
Grote and
Miracavira
Franclemont), the green pigment of
Acronicta fallax
is not sensitive to moisture degradation, where green changes to yellow upon exposure to high humidity (dried specimens of
Acronicta fallax
can usually be moisture-relaxed without loss of green colouration). This suggests a fundamental biochemical difference in the green pigment of
Acronicta
(found in
Acronicta fallax
and
Acronicta vinnula
) compared to that of psaphidines.
Figures 2-4.
Acronicta
and
Chloronycta
adults. 2a
Acronicta fallax
male (North Port, FL) 2b
Acronicta fallax
male (Hillsboro, MO) 2c
Acronicta fallax
female (Hillsboro, MO) 2d
Acronicta fallax
female (Backus Woods, ON) 2e
Acronicta fallax
male (Cartwright, MB) 2f
Acronicta fallax
male Edmunston, NB) 2g
Acronicta fallax
female (Ottawa, ON) 2h
Acronicta fallax
male (La Verendrye Reserve, QC) 2i
Acronicta fallax
male (Crooked Lake, SK) 3a
Chloronycta tybo
male (Huachuca Mtns, AZ) 3b
Chloronycta tybo
female (Cave Ck. Cyn., Chiricahua Mtns, AZ) 4
Chloronycta
sp. female (Turundeo, MEX).
Figures 5-8.
Acronicta
and
Chloronycta
male genitalia. 5
Acronicta fallax
6
Acronicta grisea
7
Acronicta tritona
8
Chloronycta tybo
. Reproduced to scale.
Figures 9-12.
Acronicta
and
Chloronycta
female genitalia. 9
Acronicta fallax
10
Acronicta grisea
11
Acronicta tritona
12
Chloronycta tybo
.
Larval morphology and biology.
The immature stages of
Acronicta fallax
were described by
Dyar (1899)
, and
Crumb (1956)
gives a brief description based on a preserved larva. Illustrations are in
Wagner et al. (2011)
and
McCabe (1991
; head capsule and mandible). Dyar described the waxy-white egg as a flattened dome with about 48 radial ridges lacking transverse striae, 2 mm across and 1 mm in
height-characters
consistent with those of
Acronicta
.
Agriopodes fallax
shares structural similarities with members of the
Acronicta hasta
and
Acronicta tritona
species groups; head often with 6-8 dark (snowflake-shaped) spots over each somewhat quadrangular lobe, D1 borne from small wart on T1, and the ground colour tends to be green and body height highest through the anterior abdominal segments in both clades. Superficially,
Acronicta fallax
shares greatest similarity with larvae of
Acronicta vinnula
and kin, a member of the tritona-group, although We cannot identify its sister taxon with certainty based on our knowledge of its morphology, behavior and natural history.
The mature larva is bright lime to yellowish green with a whitish middorsal and somewhat broader subdorsal stripe, with body tapering posteriorly. The integument is covered with abundant, minute secondary setae in the form of spinules that are slightly thickened basally, giving the integument a velvety texture. With the exception of the D1 pinaculum on T1, which is brownish to red and borne from a small wart, the pinacula are nearly obsolete in the last instar, i.e. flattened, faintly brown or concolourous, and with short setae (pinacula are more elevated and reddish brown with longer setae in middle instars). The greenish head sometimes has paired dark spots above the frons and a field of 6-8 darker spots over each lobe, laterad to apex of frons. The head, usually retracted into the thorax, has a rough, granular surface but lacks secondary setae, and is about 4 mm wide when mature. The thoracic shield is lightly sclerotized; prothorax with XD setae longest on body, extending well forward; XD1 and D1 solitary; D2 setal cluster shifted forward and grouping with XD2 seta; SD and L setae grouped, each comprised of 8-11 setae. Nearly all primary setae are replaced with open but defined clusters of 6-12 setae. Abdomen with D, SD, and L setal clusters more or less vertically aligned; D2 in typical position on A7-A10; solitary seta present below L2 group, well forward of spiracle; L3 group a diffuse set of 9-12 setae; numerous setae in each subventral cluster. A8 spiracle approximately 2
x
diameter of those on preceding segments. The anal plate and pinacula are ill defined or undifferentiated, with limits defined by clusters of microspinules, which are largest (some tooth-like) over the anal plate. Prolegs with 23-28 crochets. Length of larva at maturity is 28-30 mm. The prepupal larva turns waxy red, and tunnels into soft wood or spins a flimsy cocoon in a crevice. The larva feeds from the leaf underside of
Viburnum
species, including
Viburnum dentatum
L. (
Dyar 1899
) and
Viburnum nudum cassinoides
(L.) Torr. & A. Gray (
Wagner et al. 2011
). Undoubtedly, other
Viburnum
species are used also, particularly by northern populations beyond the range of
Viburnum dentatum
and
Viburnum nudum
. A record for poplars (
Populus
sp.) as a host cited by
Tietz (1972)
is certainly erroneous.
Figures 13-16.
Acronicta
last instar larvae. 13
Acronicta fallax
(Norfolk, CT) 14
Acronicta superans
(Norfolk, CT) 15
Acronicta vinnula
(Coventry, CT) 16
Acronicta lithospila
(
Martha's
Vineyard, MA).