Scapteriscus didactylus (Latreille) 1804

Frank, J. H. & McCoy, Earl D., 2014, Zoogeography of mole crickets (Orthoptera: Gryllotalpidae) in the West Indies, Insecta Mundi 2014 (331), pp. 1-14 : 4-6

Scapteriscus didactylus (Latreille) 1804 [= Gryllotalpa didactyla Latreille 1804 ]

Adults and nymphs have two fixed tibial dactyls which are well separated at the base ( Fig. 6 ). Adults are long-winged ( Fig. 11 ) and can fly. They are attracted readily to incandescent light. Large nymphs have short flight wings, darkly colored at the base, but these are displayed above the tegmina ( Fig. 12 ), rotating to their adult position below the tegmina at final molt. It is the large nymphs of this species that have been confused by a few authors with S. variegatus [a Central American species known from Guatemala south to Costa Rica ( Nickle 2003)].

This species was documented as a pest in St. Vincent in 1837. It is by far the major pest mole cricket in the West Indies, and was cited as a pest there by Harris (1862) who, unfortunately, did not name the islands from which he had received reports of damage [although perhaps he merely cited Kirby and Spence (1846)]. When pest Scapteriscus mole crickets arrived in Georgia and Florida ( USA) at the end of the 19 th century, they (actually three species of them together) were wrongly assumed at the time to be this one species (e.g., Worsham and Reed 1912). The individual identities and origins were sorted out by Walker and Nickle (1981): Florida’s pest mole cricket problem did not, after all, result from arrival of S. didactylus from the West Indies, but from S. abbreviatus , S. borellii , and S. vicinus from southern South America, and was largely solved by importation of biological control agents from southern South America ( Frank and Walker 2006).

Works by Barrett (1902) and Zwaluwenberg (1918) provide good accounts of the behavior, development, and economic effect of S. didactylus . The biological campaign against it in Puerto Rico (e.g., Wolcott 1938 , 1941) provides much useful information. Unfortunately, many publications after Rehn and Hebard (1916) give its name erroneously as S. vicinus because of an error of taxonomic judgment by those authors. This error influenced identifiers at museums and Wolcott and other agricultural entomologists in the West Indies to make the same error. The species’ distribution in the West Indies:

Trinidad and Tobago: Trinidad – 1901 (Anon. 1901 as G. didactyla ) – 1906 ( Bruner 1906 as S. didactyla ) – 1909 ( Nickle and Castner 1984) – 1929 ( Allan 1929, including a detailed species description of S. didactylus and statement that he had not encountered S. vicinus ).

Grenada – 1893 ( Brunner von Wattenwyl 1893, cited also by Woodruff et al. 1998) – 1905 ( Nickle and Castner 1984) – 1990 ( Frank et al. 2002).

St. Vincent – 1837 * (A letter from Mr. M’Barnet [presented by Johnstone 1837] stated that he believed “the mole cricket” “has always I believe been known in the West Indies.” That it was a species destructive to agriculture is clear from the words of Mr. M’Barnet. This mole cricket was named as Gryllotalpa didactyla by Kirby and Spence (1846 p. 136) – 1892 ( Brunner von Wattenwyl and Redtenbacher 1892 as S. didactylus ) – 1901 (Anon. 1901 as G. didactyla ).

Barbados – 1903 ( Rehn 1905 as S. variegatus !) – 1953 ( Tucker 1953, as S. variegatus !) – see previous comments concerning S. variegatus .

St. Lucia – 1889 (Two specimens in NHM labeled “ Santa Lucia G.A. Ramage June 1889 97-67” examined by J.H. Frank in September 2011 – G. A. Ramage, a collector of natural history specimens, is known to have been in the island of St. Lucia, West Indies, in 1889 ( Smith 1889) despite the unusual spelling of the name of the island) – 1896 (Saussure 1896 cited by Rehn 1905 as S. variegatus !) – 1901 (Anon. 1901 as G. didactyla ) – 1904 (Crawford Exp. St. Lucia 1904-156, specimen in NHM examined by J.H. Frank in September 2011) – 1941 (specimen borrowed from ICTA and examined by J.H. Frank in 2004) – 1973 ( Nickle and Castner 1984 examined a specimen from St. Lucia collected in 1973).

Martinique – 1952 ( Nickle and Castner 1984).

Dominica – 1901 (Anon. 1901 as G. didactyla ) – 1933 ( Nickle and Castner 1984, specimen examined and identified as S. didactylus ).

Guadeloupe – 2011 ( Meurgey 2011).

St. Christopher-Nevis: St. Kitts – 1903 (Anon. 1903 as S. didactylus ) – 1941 ( Wolcott 1941 , as S. vicinus !).

US Virgin Islands, St. John and St. Thomas – 1979 both islands ( Ivie and Nickle 1986).

Puerto Rico – 1797 * ( Frank et al. 1987, 2007 with explanation) – 1892 ( Brunner von Wattenwyl and Redtenbacher 1892 as S. didactylus , later misrepresented by others first as N. hexadactyla ! and still later as S. vicinus ! (see Frank et al. 2007 for explanation).

Haiti – 1892 ( Brunner von Wattenwyl and Redtenbacher 1892).

Dominican Republic – 1986 ( Frank et al. 1987).

*Note that the records from Puerto Rico and St. Vincent stand out as being much earlier than for any

other Scapteriscus species mentioned here. The letter by Mr. M’Barnet mentioned above stresses the

antiquity of the presence of this species at least in the Lesser Antilles.

Figures

Figures 5-8. Gryllotalpid dactyls. 5) Neocurtilla hexadactyla. Four fixed tibial dactyls. 6) Scapteriscus didactylus. Two fixed tibial dactyls separated at the base. 7) Scapteriscus abbreviatus. Two fixed and widely separated dactyls (the trochantal blade is broken off). 8) Scapteriscus imitatus. Two fixed tibial dactyls separated at the base.

Figures 9-14. Gryllotalpid habitus. 9) Neocurtilla hexadactyla. Habitus of an adult (from Grenada) with long flight wings. The cerci are prominent. 10) Neocurtilla hexadactyla. Habitus of an adult (from Florida) with short flight wings, barely protruding behind the tegmina. 11) Scapteriscus didactylus. Habitus of an adult (from Puerto Rico). 12) Scapteriscus didactylus. Habitus of a large nymph (from Trinidad) with short flight wings, darkly colored at the base, and dorsal to the tegmina before wing reversal. 13) Scapteriscus abbreviatus. Habitus of an adult (from Florida) with truncate apices of the tegmina. 14) Scapteriscus imitatus. Habitus of an adult (from Puerto Rico).