That Reptile Blog – Reptile, Amphibian and Exotic Pet Care and Information

Prehistoric cave paintings show that the pitfall trap, a simple covered or uncovered hole designed to capture animals, came into being very early in our evolution as a species.  Indeed, they are still used by hunters and field researchers today.  Pitfall traps also provide pet keepers with a simple, effective means of collecting live food for reptiles, amphibians, tarantulas, scorpions, mantids and other terrarium animals.

Building and Baiting the Trap

To create a pitfall trap, simple bury a can or jar flush with the ground and cover it with a board that is slightly elevated by small stones.  This will keep rain out while allowing invertebrates to enter.

An amazing assortment of creatures will simply stumble into such a trap, but you can increase its effectiveness by adding bait. A bit of ripe fruit, molasses, honey and some tropical fish flakes will lure all sorts of insects, sow bugs and other invertebrates (snails and slugs are especially fond of beer).  Be sure to keep some dead leaves or paper towels in the trap as well, to provide places for your catch to hide and keep away from one another.

Boards or other cover spread about an area, which can be easily turned and checked, will also attract a variety of insects. Spraying the area with a hose during dry weather will attract increased numbers of invertebrates to these shelters.

Cautions

Always use caution when examining your catch, as potentially dangerous spiders, scorpions, hornets and other such creatures may be present.  Have a good field guide on hand if you are unfamiliar with local species, and use feeding tongs to remove animals from the trap.

Native Beetles in the Terrarium

If your interests extend to native invertebrates, your trap will likely provide you with some pleasant surprises.

One of my favorite and rather frequent catches is the caterpillar hunter (Calosoma scrutator), a widespread beetle that feeds upon caterpillars and other soft-bodied insects (a relative, the forest caterpillar hunter, was imported to the USA from Europe in 1905 to battle gypsy moths).  Next time I’ll write a bit more about the natural history and captive care of these colorful, interesting, but largely over-looked beetles.

Further Reading

I have long relied heavily upon wild-caught invertebrates as food for animals in both zoo and my own collections.  In the past I have written about collecting leaf litter and arboreal insects, as well as devices such as termite traps and the Zoo Med Bug Napper.  Please see the following articles for more information:

Collecting Leaf Litter Invertebrates

Collecting Live Food: an Entomologist’s Technique

Building a Termite Trap

Collecting Live Insects for Birds

Image referenced from Wikipedia and orignally posted by

With spring finally here, my thoughts are turning to growing food plants and collecting insects with which to feed my collection.  Happily, these two activities are intertwined – plants attract insects, and insects pollinate plants.  Garden-grown plants provide minerals and trace elements that are often difficult to supply otherwise, and their fiber content is usually quite high.

Your pets’ enthusiastic attacks on novel foods will leave no doubt as to their value in stimulating appetite and behavior.  Tortoises and iguanas will spend hours happily picking through piles of fresh greens…more so if they can forage in outdoor pens atop growing plants.

Tortoises

Tortoises of all types, especially those maintained on a limited number of food items during the winter, invariably improve in condition when offered wild plants.  During the warmer months, natural forage can account for up to 85% of the diets of most species.  A pair of spur thighed tortoises, each of which weighed in at 80-90 pounds, fared very well on such a regime during the years that they were under my care at the Prospect Park Zoo.

If your tortoise or iguana is maintained on natural foods for a portion of the year, the balance of the diet can be comprised of a high quality commercial tortoise or iguana chow.

Herbivorous Lizards

Green, rhinoceros and desert iguanas, Uromastyx spp., chuckwallas and other herbivorous lizards become very excited as soon as novel fresh foods are offered.  It is difficult to get across just how much they change in demeanor but, once seen, their reactions will quickly convince you of the value of your efforts.

Aquatic Turtles

Don’t forget your aquatic and semi-aquatic turtles – cooters, American and Asian box turtles, wood turtles, Amazon side-necks and a host of others relish greens, fruits and vegetables.  Actually, painted turtles and red-eared sliders should be gradually switched to a plant-based diet as they mature.  This may take some time and creativity, but is well-worth your efforts.

The Ever-Abundant Dandelion

April and early May is dandelion-blooming time in the northern half of the USA, and nearly every herbivorous reptile relishes its leaves and, especially, the bright yellow flowers.  You can harvest this nutritious plant nearly anywhere…just be careful around homes as it is considered pest (a phenomenon that has baffled me since childhood!) and is often attacked with herbicides.

I have long used dandelion flowers to spur activity in zoo exhibits…by placing them in out-of-the-way locations, I was able to induce a great deal of interesting foraging behavior.  This was of such obvious value to the animals that I continue to freeze dandelions for winter use in my own and public collections.

Hardy Self-Starters

A number of plants that readily colonize bare patches of earth, and which need little care, are also highly valuable additions to reptile diets.  Especially hardy are clover (Trifolium), honeysuckle (Lonicera), thistle (Sonchus), bramble (Rubus) and various wild grasses.

Other types of browse that produce tasty stems, leaves and roots include various mallows (Malva), cat’s ears (Hypochoeris), Clamatis and Sedum.

Further Reading

Please see my article on Toxic Plants  for some cautions.  It was written with birds in mind, but is a good general reference.

Wild-caught insects and other invertebrates are valuable, and often essential, additions to the diets of many captive reptiles and amphibians.  During the warmer months, I have utilized them for 50-100% of the diets of many animals in my own collection, and for those under my care in zoos.

Beating the Bushes for Insects

One of the simplest and most effective collecting techniques was developed by entomologists (insect scientists) who needed to sample large habitats quickly.  Here it is: a white, un-patterned sheet is spread below a bush or tree, and the foliage is then beaten with a stick.  That’s it!

An incredible assortment of caterpillars, beetles, ants, tree crickets, katydids, spiders and other tasty morsels will rain down upon the sheet, where they can be easily collected.  The majority will be arboreal species – healthful additions to the diets of tree frogs, flying geckos, smooth green snakes and other tree-dwelling creatures, and to all other insectivorous herps.

Identifying Potentially Troublesome Species

Do not collect fireflies, “hairy” caterpillars (please see photo), and brightly colored insects that you cannot identify (due to possible toxicity).  Unless you are well-acquainted with local spiders, it is best to avoid them as well…harvestmen, or “daddy long-legs”, however, are harmless.

Use our plastic tongs to handle any specimens that may bite or sting.  A Peterson or Audubon Society field guide will help you to learn about the innumerable interesting creatures that you will encounter.

A World of Possibilities

You’ll have quite a selection to choose from, wherever you live.  Over 2,000 types of insects live right within New York City, and it is estimated that 30 million species inhabit the planet.  A single tree in Panama has yielded 130 species of beetle, 100 of which were new to science!

Last summer I was pleasantly surprised to find the spectacular eyed click beetle (Alaus oculatus) pictured below in my haul (this fellow was released).

Insect Traps and Canned Insects

The Zoo Med Bug Napper is another very useful insect-collecting tool.  An alternative means of introducing variety to your pets’ diets is through the use of canned invertebrates.

Further Reading

An amusing story involving the “bush beating” technique is given in fabulous book To the Zoo in a Plastic Box (Newmark, 1965; Random House).  A hilarious and informative account of two brothers’ adventures collecting insects and herps for the London Zoo, the book is a true gem…please read it if possible.

Please see my other insect-collecting articles as well – Leaf Litter Invertebrates and Building a Termite Trap.

Those of us who keep the smaller varieties of insect-eating reptiles, amphibians and invertebrates (dwarf leaf chameleons, bark scorpions), or who raise the young of others (many newly-transformed frogs and baby lizards), are faced with great challenges when it comes to providing a balanced diet.  Many of these animals consume dozens if not hundreds of different types of invertebrates in the wild.  Yet in captivity they must get by on very limited number of commercially bred insects – pinhead crickets, fruit flies and springtails.  Although vitamin/mineral supplements help, the situation is far from ideal, especially where little-studied species are concerned.

Special Concerns

The problem is particularly acute because nutritional deficiencies suffered early in life are difficult or impossible to reverse later on…reptiles and amphibians that remain small never outgrow this dilemma.  Those of you with an interest in invertebrates may face similar concerns when you breed mantids and certain spiders and scorpions.

An Ideal Food Source for Smaller Pets

A very simple (and free!) solution to this problem lies as close as the nearest pile of decaying leaves – leaf litter invertebrates.  A vast army of tiny decomposers and scavengers – ants, slugs, millipedes, sow bugs, beetles, mites, springtails, bristletails and termites – inhabit accumulated leaves in city gardens and pristine forests alike.

Even excluding earthworms, the weight of the invertebrates in a single acre of New England forest leaf litter can top 3 tons – greatly exceeding that of all resident mammals and other vertebrates!  So how do we get at them? More on that next week.

Other Sources of Tiny Insects

The Zoo Med Bug Napper, a very effective insect trap that I rely upon throughout the warmer months, will attract tiny gnats, moths, beetles and flies along with larger insects.  These too make fine foods for your smaller pets.

For information on a simple method of gathering termites, please see my article Building a Termite Trap.

Next time I’ll explain how to harvest and use this bonanza of free food, and my unexpected find when visiting reptile collections overseas.

Further Reading

Several tiny invertebrate species can be cultivated as food.  Please see my articles on Breeding Flour Beetles  and Sow Bugs for further information.

Isopods, more commonly known as sowbugs, pillbugs or potato bugs, are a valuable but largely neglected food source for pet amphibians and reptiles. The over 10,000 described species are common in most habitats worldwide, and are therefore an important in the diets many creatures. Ranging in size from .02 to 20 inches, there is an isopod to fit every feeding need (public aquariums pay $600 or more each for giant, deep-sea forms, so don’t plan on feeding these to your monitor lizards!).

Nutritious, Interesting Scavengers
Isopods are crustaceans, and as such provide a variety of nutrients not to be found in insects. Another thing I like about using them has to do with their appetites – they will eat anything, so by feeding them a rich and varied diet you are improving their value as food items for your pets. Furthermore, native sowbugs and pillbugs will live in most terrariums and are valuable scavengers, relishing dead earthworms, crickets and feces. I always include a group in naturalistic habitats that I design for zoos and museums. Finally, they are very interesting to observe in their own right. They do contain quite a bit of chitin, so are not suitable as the sole item in a diet.

Obtaining Isopods
Temperate isopods prefer cool, moist environments, and so are most easily found in spring and fall. You can collect them below rocks and leaf litter. They will also flock to cover such as boards placed on the ground, especially if the area is kept moist and baited with coffee grounds or ripe fruit. Biological supply houses also sell starter cultures.

Keeping and Breeding Isopods
Keep your colony in a vented plastic container with 3-4 inches of R-Zilla Coconut Husk as a substrate. Plastic terrariums by Lee, Tom Aquarium, Hagen and PLA House make ideal isopod homes. Be sure to keep the bedding moist but not wet. A covering of Zoo Med Terrarium Moss will help retain moisture and offer shelter to the isopods, making collection easier.

A mix of R-Zilla Alfalfa Meal Bedding and Tetra Min Flake Fish Food is an excellent basic diet, to which can be added grass clippings, leaf litter, coffee grounds and almost any fruit or vegetable. A cool basement makes an ideal location for the colony, but average room temperatures are fine. Be sure to keep an eye on moisture levels during hot, dry periods. A breeding colony will supply huge numbers of isopods of all sizes.

My Experience
I have always kept an isopod colony for my collection, and have used them in zoos as well. They are easy to maintain, breed readily and are, I think, one of the best-kept secrets (no more!) in herptoculture. Very few insectivorous herps refuse them, and they are readily taken by many fishes and birds as well. Be sure to try a group in your naturalistic terrariums also, as they make fine scavengers and, unlike crickets, they will not attack debilitated pets.

The University of Arizona’s Center for Insect Science Education offers a wealth of information on native invertebrates in the wild and captivity. Read more about isopods at:
http://insected.arizona.edu/isoinfo.htm