Leech Bite Clarification

Today’s Naturally Curious post stated that leeches have a chemical anesthetic which prevents the host from feeling a leech’s bite. I have since learned that there is no scientific proof of this, and substantial proof that it is not true. As reported, it is possible, and even likely, to feel a leech’s bite. In addition, as Ruth Sylvester pointed out, hirudin is the anticoagulant, not the non-existent anesthetic! So sorry. Reference: http://bdellanea.blogspot.com/2008/07/myth-busters-leech-anaesthetic.html

Mystery Photo I.D. – Leeches feeding on the blood of a Snapping Turtle

Leeches are segmented worms (annnelids) which feed predominantly on blood, although some species do eat insects. Of the 700 species of leeches, 500 inhabit fresh water, as opposed to salt water or land. Blood-sucking leeches are common parasites of many freshwater vertebrates including turtles, amphibians and fish.

Generally speaking, leeches of the genus Placobdella are commonly found on turtles. Bottom-dwelling species such as the Common Snapping Turtle, Mud Turtle and Musk Turtle usually have more leeches than other turtles, and they are often attached to the skin at the limb sockets. Aerially-basking species such as Painted Turtles often have fewer of these parasites, possibly because basking forces leeches to detach in order to avoid desiccation.

A leech can ingest several times its weight in blood from one host before dropping off and not feeding again for weeks, or even months. Leeches inject hirudin, an anesthetic, to keep the hosts from feeling them break the skin. They also inject an anticoagulant to keep the blood from clotting so that they can feed. Although leeches (especially large ones) can be a significant health detriment to smaller animals, they are not harmful to most large animals, such as Snapping Turtles.

Some of the most common predators of leeches include turtles, fish, ducks, and other birds. Map Turtles allow Common Grackles to land in basking areas and peck at leeches clinging to their skin, and minnows have been seen cleaning leeches from Wood Turtles in the water. At times turtles bury themselves in ant mounds to rid themselves of these pesky parasites.

For those readers who may hesitate before going into a leech-laden pond, it may be comforting to know that leeches are mainly nocturnal. (Photo by Jeannie Killam)

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Mystery Photo

Can you identify what is in this photo?  Submit answers on the Naturally Curious blog site, under “Comments.”  I.D. will be provided tomorrow!

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American Toad Parotoid Glands

One of the adaptations that allowed the first amphibians to spend time on land was their skin, as it helped prevent them from drying out. It also served as an effective defense mechanism.

The skin of the American Toad contains multiple glands, both mucous and granular. Mucous glands are scattered all over a toad’s body and secrete a transparent mucus secretion that acts as a lubricant in water and also helps keep their skin moist on land. Granular glands contain a toxin that deters many predators, and is a toad’s main way of defending itself. (In addition, the toxin also protects a toad’s skin from microorganisms as well as helps repair wounds.)

Sometimes clusters of granular glands form a pad, or “macrogland.” American Toads have two such pads, or s parotoid glands, which are located behind their eyes. When threatened, a toad adopts a defensive stance, inflating its body and standing with its hindquarters raised and its head lowered, a position which makes its parotoid glands the first thing that an attacking predator encounters. The secretion from these glands generally induces very serious inflammations of a predator’s eyes or digestive tract, as well as vomiting. Some predators are immune to this toxin, while others, like the American Crow, have figured out a way to prey on toads without consuming any poison — it punctures the toad’s skin with its beak and then pecks out the toad’s liver without ingesting any toxin.

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Snapping Turtle Nests Raided

Female Snapping Turtles spend a lot of time and effort finding suitable sandy soil in which to dig their nest and lay their eggs. Some turtles have been found laying their eggs as far as a mile from the nearest water source. Once she has laid her eggs and covered them with soil, the female snapper returns to her pond, leaving her eggs to hatch on their own, and the hatchlings to fend for themselves.

It is estimated that as many as 80 to 90 percent of all turtle nests are destroyed by predators, weather conditions and accidental disturbances. Most of the damage is done by predators – skunks, raccoons, foxes, crows, among others. Most nests are discovered by smell, and most are raided at night. The fluid that coats the eggs, that is lost by the mother during egg laying or is lost through breaks in the eggs, produces a smell that is easily detected by predators. While a majority of nest raids happen within the first 48 hours of the eggs being laid, studies have shown that predation occurs over the entire incubation period (June – September). The pictured Snapping Turtle nest was dug up and the eggs consumed 10 days after they were laid.

If you are aware of a spot where a turtle dug a nest and laid eggs, you can try to protect the nest from predators by placing either a bottomless wire cage or an oven rack over the nest site, and putting a heavy rock on top. The tiny hatchlings will be able to escape through the openings but hopefully, if the rock is heavy enough, raccoons and skunks will become discouraged and give up trying to reach the nest.

The next Naturally Curious post will be on 7/5/17.

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Saving Grassland Birds

Grassland birds are disappearing in the Northeast. Among the species affected are Bobolinks, whose numbers have been declining since the 1900’s. One of the primary reasons for this decline is the mowing practices of farmers. Boblinks nest on the ground, in fields. Farmers’ now mow earlier and more frequently than in the past. Their first mowing (which has the highest protein content and the greatest yield) coincides with Bobolinks’ peak nesting time. These birds migrate 6,000 miles from their wintering grounds in South America and arrive in New England to breed in mid-late May, with young hatching in mid-June. Needless to say, many of their nests fail to produce young given the current mowing schedule of many farmers.

An organization called The Bobolink Project was formed to help farmers protect grassland birds. They accept donations which they use to reimburse farmers who sign up to delay their first cut of hay. This allows nesting grassland birds such as Bobolinks, Eastern Meadowlarks, Savannah Sparrows, Upland Sandpipers, and Grasshopper Sparrows to hopefully remain undisturbed until the successful fledging of their young. To learn more about adjusting mowing schedules to outside the peak breeding season of grassland birds (May 15 – August 15) and The Boblink Project, go to www.bobolinkproject.com .

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Wolf Spiders: Maternal Duties Coming To An End

Just a few days ago, this adult female wolf spider’s abdomen was covered three-spiders-deep with newborn wolf spiderlings. Wolf spiders, unlike most spiders, do not abandon their eggs. They carry their egg sac around with them until the eggs hatch, grasping it with spinnerets located at the tip of their abdomen. Not only does the female not desert her eggs, but she also provides protection for her newborn spiders. After hatching, the several dozen or more young crawl up onto her abdomen, where they ride around for several days. Eventually they drop off and begin a life of their own. In this photo, only three spiderlings remain (look closely) and they abandoned ship within the hour.

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