Phyllomedusa trinitatis

P. trinitatis is an arboreal frog with a bright green body, black and yellow eyes, and brown chin and chest, with parotid glands near its eyes.[3][4] However, the color of the frog can differ depending on its local environment.[2] It has smooth skin on its back dotted with small tubercles throughout. The frog lacks webbing on its fore and hindlimbs.[5] Males lack vocal slits.[5]

The frog can be found throughout northern Venezuela in the following states: Distrito Federal, Sucre, Vargas, Miranda, Aragua, Carabobo, Yaracuy, Monagas, north of Bolivar and Guárico, and eastern Falcón.[6] On the island of Trinidad, it can be found in many areas including Arima, Chatham, and the Northern Range.[2]

Its natural habitats are subtropical or tropical, lowland forests, montane forests, savanna, shrublands, freshwater marshes, heavily degraded former forests, ponds, and canals, and ditches.

Researchers propose that P. trinitatis stalks its prey because of its above-average size, slow movement, and toe pad shape.[7] P. trinitatis is also known to eat insects such as Field crickets.[2]

In a study conducted in Trinidad, West Indies, researchers studied the predation of Phyllomedusa trinitatis tadpoles by the dragonfly larvae Pantal flavescens, one of the predators of P. trinitatis during its tadpole stage.[7] Researchers studied whether the larvae preferred tadpoles of P. trinitatis or Physalaemus pusulosus as prey, especially as the density of each species varied. Their results demonstrated that the relative prey density has no significant bearing on the dragonfly's preference of hunting for P. trinitatis tadpoles over Physalaemus pusulosus[7]

Before adulthood, phorid flies in Trinidad are predators of P. trinitatis eggs and often decimate entire clutches.[8]

This frog exhibits a host of defenses to evade predators and survive in hostile environments. As the frog flees from predators, it can release poison from glands found on its back.[9] Males may also remain silent rather than calling to prevent attracting predators to their locations.[9]

Furthermore, by probing the glands of P. trinitatis via electrical stimulation, scientists have isolated insulinotropic peptides from the frog's secretions. After purifying the secreted fluids of a few frogs, scientists purified four peptides that significantly promoted insulin release in BRIN-BD11 cells, cells capable of secreting insulin.[4] Researchers isolated a 28-amino acid peptide fully homologous to the C-terminal of the precursor to dermaseptin BIV.[4] These results suggest that P. trinitatis secretes an antimicrobial as part of its immune defense, though the specific mechanism of action is still unknown.[4]

Other studies have identified other defense peptides secreted from the frog's skin. One study found 15 dermaseptin peptides with varying antimicrobial properties and evolutionarily conserved amino acid regions.[10] One peptide discovered had only one cysteine residue in its structure (LTWKIPTRFCGVT), an uncommon distribution.[10] The most effective antimicrobial peptides found were phylloseptin-1.1TR and 3.1TR. Like defense proteins found in other frogs, these peptides exhibited more potency against Gram-positive than Gram-negative bacteria.[10]

Some studies provide insight into the structure-activity relationship between phyllo statins. Such studies of immunomodulation and insulinotropic activity may represent that these frogs can be used to develop drug templates for anti-inflammatory and type 2 diabetes treatment.[11]

The mating season for P. trinitatis is usually around the end of the dry season until the beginning of the rainy season.[9] The species exhibits sexual dimorphism, and females are generally larger than males.[9]

Mating rituals of P. trinitatis transpire within foliage surrounding small bodies of water, encompassing ditches and similar locales.[8] P. trinitatis is known to call out to mates similarly to other frogs. In an audio spectrogram of the call of the P. trinitatis, it was a principal note along with five secondary notes.[12] The loud call can function as a deterrent for other males attempting to seek female partners.[12] The fundamental frequency was believed to be 500 Hertz while the dominant frequencies were considered to be around 800 Hertz.[5] Additionally, more vocal males often travel greater distances in the environment. However, some males stay in place while calling out to other frogs.[13] In a realm of non-vocal communication, it is pertinent to note that male frogs exhibit a leg-waving behavior, strategically manifesting their strength as a deterrent against potential adversaries.[9] This behavior serves as a measure to preclude physical confrontations.[9]

One study focused on best practices for tracking the frogs for field research and found that neither bobbins nor radio tags were suited for the frog. Initial attempts of using fluorescent dye proved ineffective as the dye had a deleterious impact on the frog.[18] Bobbins and radio tags had no significant effect on the distance the frog traveled, even though most of the tracking devices were 15 to 20% of the frog's weight.[18] However, frogs became lethargic and less mobile by the third day of the trial. The radio tag failed to locate the frogs in areas of high altitude or vegetation as the signal became less clear. On the other hand, placing bobbins on the frogs often led to physical harm like bruising.[18]