User:Reni.Akande/Spring peeper

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Habitat and Distribution:   The spring peeper is often found in temporary ponds (which eventually dry during the summer months), intermediate ponds that have interchanging periods of being dry and wet every year, or in customarily filled ponds year-round. Although they are able to inhabit multiple types of ponds, spring peepers have been seen to be superior competitors in permanent bonds due to their higher caliber of predation resistance within the environment [1].

Diet:

The spring peeper's diet consists of filtering particles from water columns and scouring periphyton and detritus (dead, organic matter) from environmental surfaces in their habitat [2]

Reproduction and Life Cycle:

Following breeding in the spring, the spring peepers' larval stage lasts two to three months [2].

At the beginning of the mating season, the throat pouches of male Hyla crucifers begin to enlarge to a larger size than the entire head [3].

Physiology:

Female spring peepers' coloring is always lighter than the males. Protruding beyond the lower jaw of the spring peeper sits its snout. Through the use of adhesive pads located on the tips of their non-webbed fingers, spring peepers can stick to particular materials. Males and females are differentiated from one another through the darkening of the skin beneath the jaw in males. Males have a body length ranging from 18-30mm, and females have a body length ranging from 20-35mm [3].

Glands and Toxins

In Hyla crucifer males, the blackened pigmentation of the testis affects the seminiferous tubules, the underside of the peritoneum, and the organ itself. The tubules of the testis are surrounded by a pigment layer and a layer of flattened epithelial cells which are located within the surrounding connective tissue. The thickness of an average testis is about 1.10 mm and 2.5 mm in length. The spermatogonia are a cluster of masses jutting out from the tubule lumen. In the late fall, the spermatozoa, located in the seminiferous tubules of the spring peeper, mature and remain there until the spring for breeding. After the seminiferous tubules are emptied, during mating season, the pigmentation of the testis changes from black to a dull grey [3].

In the spring peeper, most of its energy is used during courtship. Higher energetic costs in female spring peepers are associated with gametogenesis, which occurs before breeding. Stored reserves of fat and glycogen contents can be measured early in the reproductive process to determine the amount used in spring peepers and their correlation to body size. Nonpolar lipid and glycogen content in male spring peepers increased with body mass, whereas in females, it decreased or had minimal variation. The fiber triglyceride and glycogen contents of the female spring peeper's liver increased significantly slower than males as body mass increased. At the beginning of the breeding season, male spring peepers have more significant amounts of bodily lipid content. Therefore, those that are larger are experiencing lower efficiencies in calling. More reserves of glycogen and lipids are required to maintain calling during the season and require additional rationing of reserves to prepare themselves for courtship. In females, there is a positive correlation between their snout length and wet ovary mass, which also correlates to an increase in body size [4].

Respiration and Circulatory System

Male spring peepers that are bigger, older, and more fit are typically superior callers. These types of males utilize citrate synthase and β-hydroxy acyl CoA dehydrogenase in their muscles at greater levels. Males with higher calling rates also tend to inhibit larger ventricles and greater concentrations of blood hemoglobin; both the large ventricle size and blood hemoglobin concentrations play a significant role in the speed of oxygen consumption, which is intensely linked to the calling rate. When a male spring peeper calls, the sound is made by the external and internal oblique muscles contract and subsequently force air out of the lungs, then move through the larynx to the vocal sac. Of the total body weight of male spring peepers, 15% is made up of the trunk muscles – which contain 2% of lipids in the body by volume – and showcase enzymes with mitochondrial markers. Calls that occur at rapid rates result in prominent energetic costs, which is why stored lipids are the source of 90% of energy applied to calling [5].

Thermoregulation

Due to climate playing a major role in when spring peepers begin breeding, one can determine that there is a clear association between temperature and breeding. Spring peepers begin to bread during temperatures that are warmer, showcasing a positive correlation between temperature and breeding time. Amphibians are exotherms, which shows that any change in the typical climate of their environment would leave spring peepers in a vulnerable position. Temperature increases can significantly impact reproduction-assigned behavior considerably [6].

Another impact that temperature has is on the duration of mating calls. There is a negative relationship between the length of mating calls and throat temperature. However, male spring peepers with superior calling frequencies are positively related to throat temperature. The temperature of the surrounding environment of spring peepers also plays a role in the rate of calls, which is positively associated with the success of males during the mating and breeding period, showing that increasing site and throat temperatures result in increasing dominant frequency [7].

Mating:

Mate Searching Behavior

With spring peepers, mating calls consist of a sound very similar to a "peep" and are repeated by males up to 13,500 times per night [5]. By looking at the different shading/coloring of concentric rings in the skeletons of spring peepers, age is able to be determined by way of bone growth. Darker lines coincide with periods of higher survival rates during winter months. Lighter lines and areas represent periods of bone deposition and rapid growth. These lines allow it to be determined that spring peepers begin to breed, going into their third spring when they are two years old. Male spring peepers have reached sexual maturity at this time yet are smaller in size than females [8]. Calls from males typically originate along the shoreline from growing vegetation or grass and shrubs along the shoreline [7]. Between spring peepers' second and third years, their body size increases significantly, then subsequentially plateaus. During the first season of breeding, the two-year-old males produce higher frequency calls than males in their third and fourth seasons, who make lower frequency calls [8].

Female/Male Interactions:

It has been established that the mating call of male spring peepers acts as an etiological isolating mechanism. As a potential agent of sexual selection, the mating call has many variations that may come into play as a major factor in mate choice by females. During mating, females monitor body size in correlation to the frequency of calls in an inverse matter. The basilar papilla of the inner ear is responsible for decoding and detecting mating calls. The basilar papilla units within the female ear are tuned between 2100 and 3700 Hz and are dependent on intensity. Females tend to select low-frequency calls more than high-frequency ones due to the easier detection of calls at the lower end of the spectrum [8]. The calls of spring peepers are often repeated, which has been deemed essential concerning the evolution of the mate choice of females reacting to particular mating and courtship behavior [7].

Home range and territoriality:

The mating displays of male spring peepers vary with different environmental factors: humidity and vegetation density. These factors play a significant role in the arboreal behavior and nature of spring peepers during mating. At sites with higher humanity and air temperature, there is increased dominance of arboreal behavior, which showcases that latitude may play a role. Spring peepers who reside in areas of warmer temperatures tend to exhibit arboreal behavior to greater extents compared to those in environments of lower temperatures. When comparing the improvement of mating calls in males, calls from above ground compared to those near the ground showcased better results. Local vegetation may also play a role in the betterment of arboreal calling compared to calling from lower levels due to the spatial aspects interrupting the call [9].

Enemies:

Spring peepers encounter enemies in their natural environments early in their development. Compared to intermediate or temporary ponds, permanent ponds host a large abundance of tadpoles and larger predators. Drying periods of ponds typically align before or during the metamorphic larval stage of spring peepers due to their slower growth rates. This suggests that higher mortality rates may be an effect. Salamanders and particular kinds of fish are seen to have profound impacts on the survivorship of spring peeper tadpoles. Each type of pond typically hosts different predators: temporary bonds host beetle larvae and dragonflies, intermediate ponds host salamanders and beetle larvae, and permanent ponds host fishes and dragonfly larvae. Each predator plays a role as a potential predator to the spring peeper, depending on which type of pond they inhabit [10].

Spring peeper larvae are thought to be poor competitors in environments where other anurans are present. This is typically due to the larval spring peepers' small size and lower levels of activity. The small size of the larval allows them to be able to deal with their depressed resource density. Larval spring peepers harvest smaller amounts of resources, resulting in them also having lower metabolic costs and a maintained growth rate. Spring peepers are said to occupy locations where predators have previously gotten ridden by bigger competitors [2].