The rough-skinned newt (Taricha granulosa) calls the Pacific Northwest home and is much tougher than it looks. It has been said, in fact that this newt can easily kill a large number of humans!! This newt has tetrodotoxin and is poisonous if in ingested. The garter snake is one of the main predators of the rough-skinned newt and the two have been having quite the arms race. The newts become more toxic while the garter snakes develop greater resistance. Watch the video below to learn more. Also, watch for the newt to show his bright underbelly in the unken reflex as an aposematic cue to warn predators of the poison.
The next video focuses more on the arms race between the garter snake and the newt. Father and son scientist team Edmund Brodie Jr. and Edmund Brodie III share their research in the video below.
The Texas Blind Salamander (Eurycea rathbuni) is in the Plethodontidae family, also known as lungless salamanders. There are over 400 species of plethodontids making them the most speciose family of salamanders. These salamanders have elaborate and stereotyped courtship rituals. Research has suggested that in general, the male initiates the mating ritual in salamanders. While research and data are sparse for Texas Blind Salamander, it has been reported in captivity that the female actually initiates the courtship behavior.
The female has been reported to rub her nose on the dorsum and side of the male near the cloacal region. Next, the female was observed to rub her cloacal region against the rocks on the bottom of the tank nearby the male. The nearby male began to show interest at this point and courtship ensued. The courtship sequence proceeded with the male depositing a spermatophore, leading the female, and finally the female’s cloaca aligned over the spermatophore to pick it up.
Courtship and sperm transfer in pygmy salamanders, Desmognathus wrighti. From biocyclopedia.com
The Texas Blind Salamander (Eurycea rathbuni) is a cave salamander that has adapted to life living in the dark. With extremely underdeveloped eyes, unpigmented skin, and the retention of its juvenile aquatic form, this salamander is perfectly suited to live in the underground cave streams. Found only in caves around San Marcos, Texas these salamanders are actually considered endangered on the State level. Because they live only in specific areas and rely on the Edwards aquifer, the Texas blind salamander is extremely susceptible to changes in water quality. Their size reaches between 3 and 5 inches and they eat a diet of most aquatic invertebrates.
Sexual dichromatism is commonly studied in birds, fish and flying postage stamps (whoops I mean butterflies), but also occurs in various other species. This is a form of sexual dimorphism where the males and females differ in color. Sometimes the male is flashy, sometimes the female, and sometimes both in different flashy ways. Sexual dimorphism of body size is common in frogs, but differences in coloration are understudied and assumed to be relatively rare. Upon closer examination in a recent review from Rayna Bell and Kelly Zamudio (link here for the full text-it’s totally worth the read) a higher incidence of sexual dichromatism exists in frogs than previously thought. The authors explain that sexual dichromatism can be dynamic- usually appearing only during the mating season or ontogenetic- which appears at sexual maturation and persists. Interestingly, they find that 31 species from 9 families have dynamic dichromatism, while 92 species from 18 families have ontogenetic dichromatism.
This review brings up several interesting points, but specifically the pressures which may be acting on each type of dichromatism. In general, during dynamic dichromatism the male frog becomes more brightly colored to attract females only during the mating season and this would be subject to sexual selection. The females are choosing the best and brightest males. However, during ontogenetic dichromatism the male changes color and remains this brighter color. In this scenario, the male hopes to attract more females during the mating season, but when mating season is over bright coloration may make him an easier target for predators (not a problem in aposematic signals). In this case, it is sexual selection as well as natural selection that may be acting on ontogenetic dichromatism.
Read more in the paper about the evolution of sexual dichromatism from the link above.
I spent the last week in the middle of Illinois teaching kids about amphibians. In our trips out to the ponds and marsh we found several cricket frogs. The class identified these frogs as Blanchard’s cricket frogs (Acris blanchardi). This frog was once considered a subspecies of Acris crepitans, but is now recognized as a separate species. Although variable in color, the dark triangle behind their head made them straightforward to identify and their abundance increased the likelihood of a successful catch. The call can be heard here and is best described as the rattle of a handful of marbles.
Male Emei music frogs (Babina dauchina) use vocal signals to advertise to females. These calls reflect genetic qualities such as physical condition, but females are also interested in resources like territories and nests. Males of this species construct burrows along pond edges and recently a group discovered that the calls from inside the nest differ from those made outside the nest. This evidence was presented in an article in Biology Letters (J. Cui, Y. Tang and P. Narrins 2012 click here for the link).
The authors found distinct differences in frog calls between inside and outside in terms of frequency range and note durations. They posit that the males are encoding information about their nest such as burrow mouth size and depth. Beyond this, females were given phonotaxis preference tests and indeed prefer the inside calls to outside calls. In short, the ladies prefer a man with his own flat. Watch the video below for an example of a call from inside a nest.
It would be interesting to see the specific female preference assesment when the call is broken down to the specific elements representing the architectural features of the nest. Does the female prefer a deeper nest and how strong is this preference?
Is it possible that males are simply altering their calls as a result of calling from inside the nest?
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.