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Predator-Prey

Rose Chafers Busy Eating & Being Eaten

6-26-15  crab spider with rose chafer 020All of a sudden we are besieged by Rose Chafers, those tan beetles that feed on roses and peonies, as well as the foliage of many trees, shrubs and other plants. The reason for their sudden appearance has to do with their life cycle.

Adult Rose Chafers emerge from the ground in late May and early June. (Because the Rose Chafer prefers sandy soil to lay eggs, plants located on sandy sites are most likely to be attacked.) Adult beetles feed on plants for three or four weeks, generally until late June when they mate, lay eggs in the soil and then die shortly afterwards. Two to three weeks later, the eggs hatch into small, white grub‑like larvae which feed on the roots of grasses and weeds. The larvae spend the winter in the soil below the frost line before pupating and emerging as adults in the spring.

Rose Chafers contain a toxin that can be deadly to birds, but apparently not to crab spiders, at least the one that was photographed drinking the innards of a Rose Chafer it had caught. As testimony to their drive to reproduce, a Rose Chafer, minutes after this picture was taken, mounted and attempted to mate with the Rose Chafer that was being consumed by the crab spider.

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Predator Eating Predator

fishing spider and dragonfly 385The Six-spotted Fishing Spider, Dolomedes triton, is an arachnid in the nursery web spider family Pisauridae. As its name implies, the Six-spotted Fishing Spider does occasionally eat small fish, but also consumes other invertebrates and tadpoles. The hunting techniques of fishing spiders are varied. Often they sit patiently during the day, waiting hours with their legs stretched out for an unsuspecting insect (such as the pictured Dot-tailed Whiteface dragonfly) to land on the same lily pad or leaf that the spider is sitting on. They can and do walk on water as well as dive up to seven inches deep in order to catch aquatic prey. The Six-spotted Fishing Spider in this photograph has removed the head of its prey and is drinking its liquefied innards.

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Eastern Newts Dining on Wood Frog Eggs

4-28-15 newts2 329Wood Frogs mate and lay their eggs in ponds and occasionally vernal pools before heading back to their terrestrial, wooded habitat. Amphibian eggs are subject to predation by numerous predators, including leeches, fish, aquatic insects and salamanders. Eastern Newts (aquatic as larvae and adults) are carnivorous and consume insect larvae, fingernail clams, leeches and amphibian eggs, among other things. At this time of year, Wood Frog eggs are plentiful and easily accessible, as the individual masses, each consisting of 1,000 to 2,000 eggs, are deposited adjacent to each other on submerged vegetation. Hungry newts can feed for hours without moving more than an inch, and many often do. After discovering an egg mass, a newt plunges its head into the clump of eggs, grabs one and, with great shaking of its head, separates an egg from the mass and quickly swallows it. Seconds later the newt repeats this process, and continues doing so until it is satiated.

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Red Foxes Locating Prey

OLYMPUS DIGITAL CAMERADeep snow certainly presents challenges to predators – their prey is well hidden for the most part, and if they are to survive, they must compensate for not being able to see what they are hunting. Foxes are an example of how a predator survives in a winter like the Northeast has had. A red fox hunting for food is constantly listening for the sound of rodent feet under the snow, and when it hears them (they can hear a mouse or vole three feet beneath the surface of the snow) they leap up into the air and pounce on or near their prey with their front feet. Most of the time they are not successful, and come up empty-mouthed, but they usually succeed often enough to survive. Biologists are still working on understanding exactly how they do this.

Researchers in Czechoslovakia, watching foxes hunt in the wild, determined that a fox’s success seems to correlate with the direction in which it jumps. If the observed foxes jumped to the northeast they killed on 73 % of their attacks. If they reversed direction and jumped exactly the opposite way, they killed 60 % of the time. But in all other directions — east, south, west, or variations thereof— they were successful only 18% of the time. Jaroslav Cerveny, the Czech researcher, feels that foxes have a “magnetic sense,” and are capable of lining up the rodent sounds that reach their ears with the slope of the Earth’s magnetic field, and when this occurs, dinner is usually caught. (This theory has yet to be confirmed, but the likelihood that it is correct is great.) (Photo by Susan Holland, in the wilds of northwest Ontario)

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Patient (and Hungry) Barred Owls Visit Feeders

3-12-15 barred owl 152Barred owls are nothing if not resourceful when it comes to methods for finding food. Typically they sit on a high branch and scan the area for prey before dropping down to capture small mammals such as mice, squirrels as well as reptiles and amphibians. During summer months, they have been seen perched over water and swooping down to capture fish, as well as wading in shallow water to hunt for crayfish and fish. Barred owls have even been seen running along the ground and pouncing on amphibians.

Even with a myriad of hunting techniques, however, barred owls have had a hard time this winter, due to the depth of the snow (harder to hear and reach prey) and the time it is taking for it to melt. Small mammals, which compose the bulk of their diet, remain well hidden. Reports of barred owls perched patiently waiting and watching on or near bird feeders for unsuspecting rodents to expose themselves have become commonplace. Mice and voles that come out from under the snow to feed on spilled seed during the night are a life-saving source of food for these stressed birds. Warmer weather will hopefully soon improve hunting conditions for barred owls. Their gain will be our loss, for once again, as it should be, a sighting will become a far more rare occurrence. (Thanks to Emily and Joe Silver for photo op.)

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Mystery Photo

Can you read this story in the snow? Hint: it took place at night on the coast of Maine. All guesses can be made under “comments” on Naturally Curious blog page. (Photo by Sally Grassi)

Naturally Curious is supported by donations. If you choose to contribute, you may go to http://www.naturallycuriouswithmaryholland.wordpress.com and click on the yellow “donate” button.2-16-15  Mystery Photo-Sally Grassi DSC_9843


Northern Short-tailed Shrews

2-4-15  northern short-tailed shrew 025Northern short-tailed shrews, with their short legs, minute eyes and concealed ears, can be found throughout eastern and central U.S. Their eyesight is so poor that all they can do is to detect light, but they compensate by using echolocation for navigation and to locate earthworms, slugs, snails and other invertebrates which comprise their diet. The northern short-tailed shrew and the European water shrew are the only mammals that produce a toxic secretion in their salivary glands. This poison is powerful enough to kill small mammals, but is mainly used to immobilize smaller prey. In winter, although active, the short-tailed shrew limits its activity in order to conserve energy, and relies partially on food that it stored in its burrow in the fall.

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