Nov 29, 2023

Public workspaceProtocol for breeding Hymenochirus boettgeri in captivity

DOI
dx.doi.org/10.17504/protocols.io.x54v9pzrqg3e/v1
  • Tamilie Carvalho1,
  • Timothy Y. James1
  • 1Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109 U.S.A.
Timothy James
Open access
DOI: dx.doi.org/10.17504/protocols.io.x54v9pzrqg3e/v1
Protocol Citation: Tamilie Carvalho, Timothy Y. James 2023. Protocol for breeding Hymenochirus boettgeri in captivity. protocols.io https://dx.doi.org/10.17504/protocols.io.x54v9pzrqg3e/v1
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License,  which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: November 20, 2023
Last Modified: November 29, 2023
Protocol Integer ID: 91222
Funders Acknowledgement:
Gordon and Betty Moore Foundation
Grant ID: 9337
Abstract
Hymenochirus boettgeri is a sexually dimorphic species, with females ty pically exhibiting a larger oval-shaped body (up to 35 mm in snout-vent length (SVL)), while males possess a large obiculated tympanum and a lateral post-axillary subdermal gland that increases in size and vascularity during sexual activity (Figure 1).
Figure 1. H. boettgeri female (superior) and male (inferior) adult individuals. Black arrow points to post-axillary subdermal gland and black bar represent 1 cm scale.

Guidelines
Conclusion:

This protocol outlines the steps for breeding H. boettgeri in captivity. Careful selection of breeding pairs, proper feeding, and attentive observation are essential for successful breeding and egg collection. Regular water changes help maintain water quality during the breeding period.
Materials
  • Male H. boettgeri specimens
  • Female H. boettgeri specimens
  • Penn Plax Deluxe Net Breeder (17.15 cm × 12.07 cm × 13.34 cm; Hauppauge, NY, USA)
  • 38 L glass tanks (25 × 30 × 50 cm) with plastic lids containing holes smaller than 1 cm in diameter for air circulation
  • Aquarium heater (EHEIM thermocontrol 75 W, Deizisau, Germany)
  • Aquarium filter (Tetra, Blacksburg, VA, USA)
  • EcoTestr CTS1 meter (Oakton, Vernon Hills, IL, USA)
  • Water testing kit (API Liquid Test Kits, API®, Chalfont, PA, USA)
  • Gravel substrate (diameter > 1 cm to prevent ingestion by the animals)
  • Artificial plants
  • PVC pipes
  • Reverse osmosis (RO) water
  • Synthetic sea salt mixture (Instant Ocean® Sea Salt, Blacksburg, VA, USA)
  • Sodium bicarbonate
  • Brine shrimp (Artemia sp., BIO-MARINE®, Hawthorne, CA, USA)
  • Frozen gamma-irradiated bloodworms (Chironomus sp., Tropical Marine Center, UK)
  • Powdered fry food (Sera® Micron Nature, Heinsberg, Germany)
  • Small-granule fish food (BUG BITESTM Tropical Formula, Mansfield, MA, USA)
  • Nitrifying bacterial suspension (ProLine® Aquaculture Bacteria Concentrate, Apopka, FL, USA)
  • Tricaine methanesulfonate (MS-222; Syndel, Ferndale, WA, USA)
  • VirkonTM Aquatic (LANXESS, Pittsburgh, PA, USA)
Sexual selection
Sexual selection
Select male H. boettgeri specimens with heavily vascularized glands and the largest females for breeding.
Note
Sexual maturity will depend on the conditions in which the animals were raised (e.g., space, diet, temperature). Observing the glands in males and an increased body size in females will indicate that they are sexually mature. In our systems, the male glands were first observed at 5 months of age, and females spawned for the first time at a minimum of 6 months of age.

Keep males and females in separate 38 L glass tanks by sex at Temperature25 °C with conditioned water as described in the “Housing and Care for Hymenochirus boettgeri” protocol and 13:11 light-dark cycle.
Feeding
Feeding
Feed the frogs ad libitum twice per day for ten consecutive days, providing newly hatched brine shrimp as the first meal of the day, and offer either frozen gamma-irradiated bloodworms, live blackworms, or small-granule fish food as the second meal of the day, changing the combination daily if possible.
Pair selection
Pair selection
After 10 days of enhanced feeding, choose breeding pairs consisting of one male and one female each.
Mating tanks
Mating tanks
Using an aquarium net, place each breeding pair in separate 8 L plastic tanks at 21 °C, with a minimum water volume of 2 L per individual.
Note
These tanks should not have any enrichment, filters, or heaters to facilitate egg visualization and collection.

Allow the breeding pairs to remain together for one to four days, during which mating behavior is expected.
Observe the frogs closely during this period. If the pair does not reproduce, consider replacing one of them with another animal to create a new pair combination.
Egg Collection and maintenance
Egg Collection and maintenance
After mating, collect the eggs as they are laid using a sterile siphon or spoon and transfer them to net breeder tanks as described in “Housing and Care for Hymenochirus boettgeri” protocol.
Check the eggs daily and remove any that contain fungi growing or that haven't hatched after 4 days of being laid.
Water safety
Water safety
During the breeding period, feed the animals and, if necessary, perform a water change as described in the “Housing and Care for Hymenochirus boettgeri” protocol.