Chiasmocleis ventrimaculata

The Amazon is the center of intense degradation because of human occupancy, deforestation, and mining. As a result, there are large parts of the habitat that are at risk.[7]

Chiasmocleis ventrimaculata and Chiasmocleis species in general are not listed as threatened by the IUCN and most of the species are listed as Least concern.[7]

C. ventrimaculata has several close relatives: Chiasmocleis albopunctata; C. anatipes; C. antenori; C. avilapiresae; C. bassleri; C. carvalhoi; C. devriesi; C. haddadi; C. hudsoni; C. magnova; C. papachibe; C. royi; C. shudikarensis; C. supercilialba; C. tridactyla.[7]

Chiasmocleis jimi is considered a junior synonym of Chiasmocleis hudsoni.[7]

Males will make calls during the breeding season that consist of a series of short pulses (7–8 per second). The frequency range for these calls falls within 5.120–6.960 Hz.[4] These males will move so that their vocal sacs are elevated so that females will be able to hear their calls.

Mating occurs during most of the day but particularly from 8:00 pm to 4:00 am. The females that are attracted to the males will move into the water towards the males, and the males will then jump into the water to perform amplexus. The males do not vocalize during amplexus, and this lasts up to 30 minutes.[4]

This frog is primarily known for its mutualistic relationship with the burrowing tarantula Xenesthis immanis.[6] Whether or not the relationship is mutualistic or commensal still dominates conversations surrounding this species. It is clear the dotted humming frog greatly benefits from this relationship, as the tarantula provides the frog protection from predators, a stable food source due to the frog's ability to feed off the remnants of the spider's prey, and shelter to protect from climate variations.[10] On the other hand, the frog's foraging protects the tarantula's eggs from ants. The relationship between this specific frog and Xenesthis immanis appears to be a special one as these tarantulas attack similar frog species, therefore showing the dotted humming frog must have a special feature attractive to tarantulas. This mutualism between microhylids and large spiders also occurs in other parts of the world.[3]

Tarantulas emerge from their burrows and dotted humming frogs closely follow, and although the tarantula would be expected to attack, they do not.[10]

It has been hypothesized that the tarantulas might benefit from this relationship due to the fact these frogs are ant specialists, which can help them protect female spider's eggs from predation, increasing the fitness of female spiders who have these frogs in their burrows. Alternative suggestions include the skin of these frogs containing antimicrobial chemicals which help keep the spider eggs healthy and that because these frogs can attract predators, tarantulas with frogs in their burrows have access to more food because they can then eat these predators. Furthermore, there is contention on the species of spider that these frogs coexist with. Originally thought to be Xenethis immanis,[6] further research has found that this species of spider would not be found in the regions of Peru where the original research was conducted. Instead, new research suggests that the tarantula is some species of Pamphobeteus.[9]

The tarantulas have been recorded attacking similar frog species to C. ventrimaculata, but have been never recorded attacking C. ventrimaculata by mistake. The movements of the frog do not stimulate the host tarantulas to attack and there is an unknown chemical present in the frog's skin that acts as a cue to the tarantulas that this species is not prey.[9] The spiders did attempt to catch and eat five species of frogs from the families Bufonidae, Hylidae, and Leptodactylidae. It is noted that the frogs will remain more active in areas with some vegetation while the spiders used the open area.[10]

As tadpoles, Chiasmocleis ventrimaculata are often preyed upon by freshwater crustacean species such as Dilocarcinus and Goyazana. They have also been seen being eaten by Odonata larvae. In addition, turtle species such as Phrynops gibbus and Podocnemis unifilis are also known to feed on tadpoles. Spider species are known to prey on adult frogs and fish like Hoplias malabaricus, Synbranchus marmoratus also feed on frogs and tadpoles alike. Caimans have also been seen preying on these frogs. There are a wide variety of bird species, including capped herons, sunbitterns and double-toothed kites, which have also been seen feeding on the frogs and their young as well, although snake species appear to be the main predator of these frogs. Even certain species of bats, suspected to be Trachops cirrhosus, have been seen trying to feed on frogs during mass mating calls.[4]

Chiasmocleis ventrimaculata have cryptic camouflage which allows them to resemble fallen leaves. In addition, when threatened these frogs will make a short leap and land with their legs stretched backwards in a stiff-legged posture. This behavior has been seen to last up to 4 minutes.[4]