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Neoscapteriscus didactylus (Latreille)
(Ney-oh-scap-terr-ISK-us did-AKT-ill-us)
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Distribution
The West Indian mole cricket arrived in Puerto Rico, from northern South America, before 1797. It is currently found on Puerto Rico, St. Thomas (Virgin Islands), and St. John (Virgin Islands).
The common name of Neoscapteriscus didactylus (Latreille) is “la changa” in Puerto Rico. It has also acquired the name the “West Indian mole cricket” in some English-language publications.
Description
The changa, or West Indian mole cricket, is a mole cricket of average appearance, the thorax of tawny color, and wings longer than the body. When captured, it will often “play dead” like the southern mole cricket.
The color pattern of the dorsal side of the thorax is helpful in distinguishing between Neoscapteriscus species. In this species, the pronotum is light and distinctly patterned. The pronotum in this species is oval, about one-half longer than it is wide.
The space between the tibial dactyls is important, but cannot be seen without a magnifying lens or microscope. The tibial dactyls of the West Indian mole cricket have an interdactyl distance of greater then 0.15 mm. The tibial dactyls are moderately separated.
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The left foreleg – inner side – of a West Indian mole cricket.
The general appearance of the various species distinguishes them when they are compared or when the observer is familiar with them, but is difficult to put into a short but easily understood written description. The behavior of living adults of the species helps to distinguish them when they are captured alive. The songs of males of the four species that sing separate them very clearly and without question, but require electronic equipment for precise analysis. The songs can be heard, remembered, and distinguished by anyone with a musical ear.
Life Cycle
The following account is of the West Indian mole cricket species in Puerto Rico. Its seasonality probably is identical in St. Thomas and St. John, but has not been studied there. In captivity, females were found to lay eggs in all months of the year except December, though most were laid in April, May, and June. The greatest number of eggs laid per female was 110, divided into four clutches. Nymphs hatch from eggs in about three weeks. The total development time from egg to adult is nearly 300 days on average, which is twice as long as for the tawny mole cricket in Florida. Despite the much longer development time of the nymphs, there may be just one generation each year, as for the tawny mole cricket in Florida. All stages may be found in the field throughout the year, which is not true of the tawny mole cricket in Florida. Adults fly in large numbers in October, November and December, and are attracted to incandescent lights.
Damage
The West Indian mole cricket is a major pest of vegetable seedlings and turf. This mole cricket includes ants in its diet, and may perhaps feed on fire ants, among other ants.
Larra bicolor, a species of crabronid wasps was introduced from Amazonian Brazil into Puerto Rico in the 1930s to combat Neoscapteriscus didactylus(Latreille). The wasp established populations at least along the northern coast of Puerto Rico, but nobody seems to have evaluated the effect of the wasp against this or other mole crickets in Puerto Rico. What we do know, from a study published in 1984, is that this mole cricket is not attacked very successfully by the wasp, which is more successful in attacking Neoscapteriscus abbreviatus (Scudder), the shortwinged mole cricket. In the late 1970s to early 1980s, wasps from the established population in Puerto Rico were introduced into Florida, and a wasp population thus became established in Ft. Lauderdale, but not farther north.
