Orthoptera

Nicholson, Daniel J., Tapley, Benjamin, Jayson, Stephanie, Dale, James, Harding, Luke, Spencer, Jenny, Sulton, Machel, Durand, Stephen & Cunningham, Andrew A., 2017, Development of in-country live food production for amphibian conservation: The Mountain Chicken Frog (Leptodactylus fallax) on Dominica, West Indies, Amphibian & Reptile Conservation (e 149) 11 (2), pp. 59-68 : 60-62

Orthoptera

Orthopterans represent a large proportion (44%) of the known diet of L. fallax on Dominica ( Brooks Jr 1982) . Cultures of two cricket species were established at the start of the project: G. sigillatus ( Fig. 2A ), and C. dominica ( Fig. 2C ). A colony of G. assimilis ( Fig. 2B ) was formed four years after the facility was set up in order to increase the variety of live food being offered to captive L. fallax . The founding population of C. dominica was collected from forested areas around the island. Gryllus assimilis colonies were established from just two found- ers that were collected using baited bottle traps. No other individuals of G. assimilis have been observed on the island since the original opportunistic encounter. Gryllus assimilis and C. dominica are native to Dominica and the West Indies ( Orthoptera Species File 2016, Weissman et al 2009). Gryllodes sigillatus is a southeast Asian native but is now globally distributed ( Otte 2006). Individuals used for culture were wild-caught in-country.

Housing: Orthopteran colonies were housed in clear plastic containers measuring 52 × 36 × 38 cm, with an open top covered with fine fly mesh to prevent escape ( Fig. 3A ). Refugia, including cardboard (hens’) egg boxes and cardboard tubes, were provided. Housing containers were cleaned monthly (for G. sigillatus ) or twice monthly (for G. assimilus and C. dominica ) to remove faecal waste; uneaten food was removed three times per week.

Feeding: Orthopteran colonies were fed fresh food three times per week. A number of different fruits and vegetables were provided, including pumpkin (1 cm cubes), lettuce (diced), cabbage (diced), and carrots (0.5 cm thick discs, halved). Also, a teaspoon each of Seminole Feed® Premium Performance Dog Food (Seminole Feed, Florida, USA) and Pentair® Colour Mix Fish Flake Food (Pentair Aquatic Eco-Systems, North Carolina, USA) were provided to each container three times per week. These were used due to their high protein content (dog food: 26% protein, fish food: 45% protein) and ease of storage.

Breeding: Oviposition sites were created using a 1:1 mix of compacted sand and sphagnum peat moss placed into (10 × 5 × 5 cm) plastic containers (margarine tubs). These were removed from housing units after two weeks, or sooner if hatchlings were observed ( Fig. 3B ). After removal, oviposition sites were placed into separate housing units until all 1 st instar crickets hatched and exited the nest box. The substrate in the oviposition sites was kept moist at all times.

Rotation: All housing units were arranged and rotated depending on instar. Once the oldest adult crickets had been given sufficient time to lay eggs in the allocated oviposition site and provided with a respite and feeding period, they were fed to the captive L. fallax population. The associated oviposition sites were then placed in the first housing unit of the rotation and the remaining crickets at the most advanced stage of development were provided with an oviposition site.

Figures

Fig. 2. Cultured species at the CBP in Dominica. (A) Gryllodes sigillatus. (B) Gryllus assimilis. (C) Caribacusta dominica. (D) Blaberus discoidalis. (E) Zophobas atratus. (F) Veronicella sloanii. (G) Pleurodonte dentiens. (H) Leptogoniulus sp. Photos: D. Nicholson.

Fig. 3. (A) Two rows of cricket breeding containers and cockroach breeding bins below. (B) Inside of a cricket breeding container, including refugia, food items, and several egg laying containers, transplanted into an empty container to allow eggs to hatch. (C) Inside view of a cockroach breeding bin, including substrate, refugia, and several food items. Photos: D. Nicholson.