Tag: forest

  • Can Frogs Really Predict the Weather?

    Can Frogs Really Predict the Weather?

    Frogs are weather experts. Some frogs and toads, based on their croaking, egg-laying, and even skin color, are said to allow us to predict whether it will rain soon or not. But what is the truth behind the frogs’ purportedly preternatural weather forecasting abilities?

    Long ago in Switzerland, if you would put a tree frog in a jar half full of water and give it a little ladder to climb, it could forecast good weather by climbing the ladder and bad weather by descending back into the water. Even today, in Germany, a weatherman is referred to as a Wetterfrosch, which translates as “weather frog.”

    Tree frogs are known to climb trees in favorable weather and make an awful noise, croaking sweetly for hours on end, thus the frog weather prediction theory actually has some validity.

    Monitoring the Humidity

    Numerous accounts point out the daily behavioral changes in amphibians and some reptiles related to predicted weather. Some species, for instance, become more active just before it starts to rain, while others are more likely to make their distinctive croaking sounds. The weather probably has a lot to do with this shift in behavior.

    Frogs and toads are highly reliant on accurately monitoring the humidity or temperature of their surroundings. That’s because amphibians are ectothermic, meaning they don’t produce their own heat. So, their blood, muscles, and skin, along with the rest of their organs, are always at the same temperature as their surroundings.

    Exceptionally Sensitive to Moisture Levels

    Frogs’ skin is very porous because of the abundance of glands on its surface. Because of this, they suffer significant water loss due to evaporation. But frogs and toads have a more refined sense of moisture via their skin than people do. In the tropics, for example, certain frog species usually come out of the underbrush when the humidity rises in anticipation of rain.

    Finally, amphibians like frogs and toads produce their offspring in aquatic environments. Thus, in order to effectively reproduce, they have to predict when there will be adequate puddles and pools from rain in which their tadpoles may grow. This means that when the weather or temperature changes, frogs have to adjust their behavior accordingly.

    Climbing Tree Frog

    So why then do frogs choose to remain low when bad weather is approaching, yet climb up when conditions are favorable? There are no precise investigations of the topic available. However, there are two theories among frog scientists as to why this occurs: The tree frog, in contrast to most other frog species, enjoys vertical environments and bright sunlight. Male frogs, especially those still in their juvenile stages, spend most of the late summer sitting on bushy branches and leaves to soak up some rays.

    However, the accessibility of food is equally important. The same goes for tree frogs, who also utilize their perches to swoop down on prey. Insects like mosquitoes are sensitive to weather changes, something our ancestors accounted for in their agricultural guidelines. With less wind and more sunshine, insects may ride the warm updrafts to greater heights in their flights. They tend to linger on the ground if a severe wind and a drop in temperature are expected.

    It is unknown, however, whether tree frogs actively pursue prey higher or lower, or if they instead respond immediately to changes in the weather. One thing scientists can agree on is that frogs and toads frequently respond to a shift in the weather before humans do. And this, of course, has nothing to do with clairvoyance.

  • Why Do Some Female Spiders Eat Their Mates?

    Why Do Some Female Spiders Eat Their Mates?

    Why do some female spiders eat their mates? You frequently hear the words “I love you so much” said between people newly in love. However, there are certain creatures who take this remark to a new level. They eat members of their own species, sometimes even when they’re mating. Particularly, spiders have a bad name for engaging in “sexual cannibalism.” The black widow spider has gained as much notoriety as the red-backed spider and the native cross spider for its reputation as a predator of male humans. Nevertheless, why do female spiders kill and eat males?

    Sexual Cannibalism

    Sexual cannibalism may be split into two distinct subtypes. The first involves females eating a male before mating, either out of hunger or to prevent mating. This is a common occurrence in a wide variety of animal species. However, this only applies to a tiny fraction of males and is by no means the norm.

    Sexual cannibalism also occurs during and immediately after the mating act. Scientists have discovered that females of certain species will systematically murder males if they so desire. For instance, Latrodectus hasselti, known as the Redback spider or the Australian black widow spider, and Argiope spiders fall within this category. Wasp spiders, recognizable by their striped abdomen of yellow, white, and black, are also members of this family.

    The Reason

    But why would the supposedly cruel and merciless female spiders engage in such strange behavior? They do this so that they may continue mating with different males while keeping the duration of copulation, or sexual intercourse, to a minimum. Finding a mate with the finest genes to inseminate the eggs is the main objective of mating for female spiders.

    In addition, the male spider makes a pleasant source of food and energy for females when consumed after being slain. There is a clear advantage to the children from this as well. Studies have shown that female spiders that consume males have bigger clutches (total number of eggs) than female spiders who are not allowed to consume males.

    Mating Length is the Key Factor

    Even yet, some male spiders still make it through the initial mating without being attacked by the female spiders. Variation exists even within species when it comes to the mortality rate of males following the first successful mating. Males that don’t mate for long enough are also at a higher risk of being eaten.

    Those males who get out of the encounter unharmed, however, don’t attempt to get away and instead go through with a second mating, which almost always ends in tragedy. Unfortunately, this still raises one’s odds of becoming a father and having offspring. When a male tries to push his luck and, in the end, sacrifices himself, this still lets him fertilize more of the female’s eggs.

    Before making love, the St. Andrews Cross spider (Argiope keyserlingi) uses a webbing to tie its mate to itself. Keeping the male around for longer may be desirable from the female’s perspective if she hopes to increase the number of eggs that are fertilized.

    Mates With Smaller Sizes Are More Likely to Be Eaten

    However, sexual cannibalism in spiders does not always seem to be caused by competition for evolutionary benefit. Researchers claim to have identified an alternative cause for this behavior. They claim that when men are physically inferior to their female companions, they are more likely to be eaten. This is true of many species, including the North American wolf spider, Tigrosa helluo.

    It is interesting to see that a seemingly insignificant factor—the size gap between sexes—plays such a crucial role in determining sexual cannibalism. The trade-offs involved in sexual cannibalism are usually rather simple. When a hungry female spider comes upon a “boyfriend” tiny enough to trap, she can’t stop the urge.

    Praying Mantises Also Show This Behavior

    The practice of eating and being eaten is not limited to the sexual partners of spiders. Scientists have known for a long time that the phenomena occur in various clades of animals. Some insects, including praying mantises, have earned a reputation for this behavior. These insects’ males have a very perilous existence before, during, and after mating. One Asian species, Hierodula membranacea, has females that have been seen biting off the males’ heads during intercourse; however, the sexual act continues undisturbed.


    Sources:

    • Sexual Cannibalism: Why Females Sometimes Eat Their Mates After Sex. (n.d.). Discover Magazine.