Scapteriscus imitatus Nickle and Castner 1984

Frank, J. H. & McCoy, Earl D., 2014, Zoogeography of mole crickets (Orthoptera: Gryllotalpidae) in the West Indies, Insecta Mundi 2014 (331), pp. 1-14 : 7-8

publication ID

https://doi.org/ 10.5281/zenodo.4531680

publication LSID

lsid:zoobank.org:pub:EDD2E0AA-A581-4AEE-A494-7E5EF21F9D0B

persistent identifier

https://treatment.plazi.org/id/03FA878C-FFC1-FF8F-10E7-DBEEEA07FC39

treatment provided by

Felipe

scientific name

Scapteriscus imitatus Nickle and Castner 1984
status

 

Scapteriscus imitatus Nickle and Castner 1984

Its foreleg, showing spacing of the two fixed dactyls ( Fig. 8 View Figures 5-8 ); and its habitus ( Fig. 14 View Figures 9-14 ), showing it as a smaller, darker, and more slender mole cricket, distinguish it from S. didactylus . It has no recognized pest status. The species’ distribution in the West Indies:

Puerto Rico – ca. 1940 ( Nickle and Castner 1984, although the first Puerto Rican specimen they saw was collected in 1982). It seems now to be restricted to a small area in northwestern Puerto Rico ( Frank et al. 2007).

Records of two other species in the West Indies appear to be erroneous. All of the published records of Scapteriscus vicinus in the West Indies seem to be based on misidentification. A few erroneous records of occurrence in the West Indies of S. variegatus exist. Barbados (1903; Rehn 1905): “ Barbados. July 10, 1903. (H. A. Ballou). [No. 224]” One male.” “This specimen has the wings shorter than the tegmina, in this resembling S. abbreviatus Scudder , which, however, has the tegmina of a very different shape. The species ( S. variegatus ) has been recorded from St. Lucia by Saussure.” Rehn (loc cit.) believed this to be an adult of a short-winged mole cricket that was not S. abbreviatus . It is almost certainly a large nymph of S. didactylus , however (see Fig. 10 View Figures 9-14 and explanation below). Barbados (1953; Tucker 1953): “ Scapteriscus variegatus Burmeister – Specimens taken under a dripping tap, also in a muddy situation.” This record was reported uncritically by Bennett and Alam (1985), pers. comm. from F.D. Bennett to J.H. Frank on 7 Feb 2011. St. Lucia (1896; Saussure 1896): Cited by Rehn (1905). This probably is another misidentification of a nymph of S. didactylus , which is reported from that island by Nickle and Castner (1984). This erroneous record may be what led Rehn (1905) to misidentify a S. didactylus nymph from Barbados, another of the Windward Islands. Locality unknown, University of Iowa, “ Scapteriscus variegatus , B 1047. 013.” The specimen was later identified by Caudell (1922) as S. abbreviatus . Its origin is obscure, but perhaps the West Indies.

The records of Scapteriscus variegatus (Burmeister) from Barbados need further mention. The identity of a specimen discussed by Rehn (1905) as having been collected by H. A. Ballou in Barbados in 1903 is unclear. Rehn (1905) stated that the wings are shorter than the tegmina, which are “of a very different shape” from those of S. abbreviatus , and he attributed it to “ S. variegatus (Burmeister) .” Caudell (1922) commented on Rehn’s interpretation, but drew no new conclusion. Tucker (1953) mentioned two specimens from Barbados that he attributed to this same species. “Short-winged” mole cricket specimens from elsewhere, Trinidad, suggest another interpretation. Final instar nymphs of S. didactylus have developing flight wings as long as 40% of the length of the abdomen. In repose, these wings are dorsal to, and longer than the tegmina; not until the nymphs molt to the adult stage do the tegmina rotate to assume the dorsal position seen in the adult, a phenomenon known in Orthoptera as wing reversal. [An instance of this in instar VI of Schistocerca americana (Drury) is illustrated by Capinera 1993.] At first glance, it thus appears that the flight wings are the tegmina – but their apices are pointed, unlike the truncate tegmina of S. abbreviatus , and their venation is unlike that of tegmina. Furthermore, the bases of the flight wings are darkly pigmented in S. didactylus nymphs as the basal venation of the tegmina of S. variegatus was reported to be ( Nickle 2003). It is likely, therefore, that Rehn (1905) mistook a large nymph of S. didactylus ( Fig. 10 View Figures 9-14 ) as an adult of S. variegatus ; if the specimen examined by Rehn was returned to the collection of the Department of Science and Agriculture in Barbados as seems probable, this would also account for the listing of S. variegatus by Tucker (1953) in that island without mention of S. didactylus . This scenario makes sense in that S. didactylus is known from the neighboring islands of Dominica, Grenada, Martinique, St. Lucia, St. Vincent and Trinidad, whereas no specimens of a shortwinged (adult) mole cricket from those islands have been found there.

We plotted the first records of occurrence (rank) on West Indian islands against the distances of the islands from South America (rank). The relationships for the two widespread species capable of flight are shown in Fig. 15A, B. The similarity of these relationships is not surprising, as extensive collection in one area is likely to have revealed both species, even if one or both species initially were misidentified. Neither the strong tendency for earlier records to be nearer South America, nor the apparent division of islands into separate “groupings” is readily explainable, based on the historical record. It is possible, for instance, that British entomologists based perhaps in Barbados searched systematically for pests south to north in the Lesser Antilles, but we have not encountered any statement to that effect. That these two relationships parallel our proposed dispersal pathways for the species (see below) may be entirely fortuitous, but the matter would seem to warrant further examination. The relationship for the flightless species is shown in Fig. 15C.

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Orthoptera

Family

Lathiceridae

Genus

Scapteriscus

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