Etymology. This new genus is dedicated to the authors’ friends, Heidi and Joseph Parker, on theoccasion of their marriage and honoring Joe’s workon pselaphine inquilines. In early 2015, Joe and Heidi became parents of Jonah Wallace Parker (7 lbs. 10 oz.). – Source: Morgan Jackson
Reproductive modes in frogs vary greatly, as do the ways in which they deposit their eggs. The túngara frog, Physalaemus pustulosus (=Engystomops), which is the main focus in my lab constructs a “foam” nest–an adaptive character which I’ve become interested in exploring. Foamy substances are produced by some insects, tunicates, fish and, perhaps most famously, frogs.
Foam nests may be constructed by frogs in trees, underground burrows, on top of water, or nearby water sources. This phenomenon has evolved independently several times in both old and new world frogs, living in tropical and subtropical areas.
(Pleurodema diplolister foam nesting – Video Credit: Amphibiaweb.org – Watch the video above to learn more about foam nest construction)
To form the nest, a gooey gelatinous substance comes out alongside the eggs, and it’s usually the male who whips the substance into a bubbly foam using his back legs. Biologically, these nests are incredibly resilient and able to withstand mechanical forces and environmental hazards.
Depending on the frog species, as well as individual differences within species, embryos and then tadpoles vary in the amount of time they spend in nests before emerging. The nest is thought to protect tadpoles from predators, and also maintains a moist environment to prevent desiccation. The foam nest may additionally provide the eggs with more exposure to oxygen (a hypothesis I’m currently testing experimentally in the túngara frog).
Fig 2: a) foam nest from above b) illuminated from below c) cross-section d) natural foam nest placed on a petri dish (from Dalgetty and Kennedy 2010)
A member of the family Leptodactylidae, the túngara frog is found in Central and South America, The male constructs the nests on or near temporary pools of water. The structure of the foam nest is shown in figure 2 (note the “cortex” of foam surrounding the eggs, evident in 2c).
(túngara frog nest construction – Video Credit: Amphbiaweb.org)
Nests may be singletons or many nests may be connected to one another. Community building is discussed in detail in a paper from Dalgetty and Kennedy in 2010 where three distinct stages of nest building in the túngara frog are explained: 1) creating a bubble raft 2) main building and 3) termination. By exploiting the community nest, pairs spend less time on phase one. While it is unclear if community building is advantageous for all frogs within a given community, it is likely to be so for late joiners, who can skip the first stage of raft building, leaving the early birds to do more of the work–a classic example of the tragedy of the commons.
Stay tuned to this post in the future, where I’ll provide updates of my experimental findings. In the meantime, check out the papers below to learn more.
Dalgetty, L., and M.W. Kennedy 2010. Building a home from foam–túngara frog foam nest architecture and three-phase construction process. Biol. Letters. vol. 6 no. 3 293-296
Flemming, R.I., Mackenzie, C.D., Cooper, A., and M.W. Kennedy (2009). Foam nest components of the túngara frog: a cocktail of proteins conferring physical and biological resilience. Proc. R. Soc. B. vol. 276 no. 16631787-1795
This has been a RAmBlN blog post: part of a series on herpetological adaptations, in celebration of Darwin Day 2014. Check out the other posts here! Like us on Facebook! Or follow us on twitter!
There are loads of salamanders that don’t necessarily fit into our idea of a salamander. The amphiuma is one example. There are three species of one-, two- and three-toed salamanders and all are fully aquatic. Depending on the species they can be between 33 and 110 cm, but their legs stay T-rex style. They inhabit the southeastern United States, and although relatively common they are sadly understudied.
Here is a video to learn more:
Even though the legs are vestigial, the amphiuma is still able to traverse across land.
I am lucky enough to spend my days in a frog communication lab, but everyone on the street knows how frogs communicate-by calling (if you didn’t know that, I’m really sorry about the sad life you’ve been living. Please go outside today and sit in the grass. Maybe quit your job. Also, let your parents know you’d be better off if you were raised by wolves because at least then you’d know the glory of nature).
In general, we think of frogs calling from the edge of the pond where the only competition is from other male frogs. It gets more interesting when you consider some frogs call near rushing water and the modifications they must make to their call. Calling is energetically costly and competing with rushing water can surely be exhausting. Some frogs have developed another mode in which to signal by using semaphore. Indeed, the frogs of the genus Staurois from Borneo still call, but the streams are so loud that they modify their call and employ this semaphore in the form of foot flagging.
In short, when times get tough for frogs and the party is just too loud to scream and get your friend’s attention, these guys wave their legs to make it happen. Thanks evolution and glad you could make it to the party.
There is a recent natural history article in the Journal of Herpetology (click here for the link from D. E. Lee et al., 2012) describing the Arboreal Salamander (Aneides lugubris). The authors have characterized the basic life history traits of this salamander by capture-mark-recapture studies covering a 4 year span. This information is important for many areas of future research, but specifically this will aid in future conservation endeavors.
Oh yeah and this little guy has TEETH!
Basic life-history information like this is still lacking in many species because it is difficult to find funding. Check out the link above to read more about this salamander or click here to see more California salamanders.
Last week, the Natural History Museum in London unveiled a digital archive of the letters of 19th century naturalist Alfred Russel Wallace, the co-discoverer with Charles Darwin, of evolution by natural selection. The archive, introduced on the 100th anniversary of Wallace’s death, naturally focuses on his writings, but also contains some paintings and drawings. Wallace, who spent years in far-flung places collecting specimens, didn’t have the option of pulling out a camera to document his finds. He often sketched or painted his discoveries, including this lovely watercolor of a flying frog which he painted in Sarawak. It may not be Audubon-level in its artistry and detail, but it’s a useful scientific illustration which also has great personality and charm.
