Natural History of the Ornate Box Turtle, Terrapene ornata ornata Agassiz

by John M. Legler

Exposed bone on the shells of turtles that have been injured in fires, although dead, is unmarked and shows no evidence of being burned. Exposure to fire kills the growing portions of both the epidermis and the bone but seemingly does not actually char or disfigure the bone (although the epidermis may be so affected) ([Pl. 29, Fig. 3]). Injuries from fire result probably from brief encounter with the fire itself or from more prolonged contact with some surface heated by the fire. A turtle that remained in a fire long enough to have its shell charred would presumably have little chance of survival. Grossly disfigured shells therefore do not result directly from burns but are due to the gnarled texture of the regenerated bone and epidermis remaining after the dead portions of the shell have been sloughed off. Information on injuries from fire was supplemented by examination of several badly burned specimens of T. carolina. Their shells were nearly covered with exposed bone and regenerated epidermis. One specimen was so badly damaged that the entire anterior rim of its carapace was loose and could be pulled away easily to disclose a gnarled mass of regenerating bone beneath it ([Pl. 29, Fig. 3]). There were areas near the posterior margin of the carapace of each specimen where regenerated epidermis was evident but where the bone was seemingly uninjured; the regenerated epidermis was nearly transparent.

Areas of regenerated epidermis on specimens of T. ornata were rough in texture and slightly paler than the surrounding scutes. Color-pattern is not reproduced in the process of regeneration but irregularly shaped light blotches sometimes occur in the places where radiations or other distinct markings formerly were present. A slight depression remains on the shell after regeneration is completed. I suspect that small injuries may be repaired in the course of a single growing season but that injuries involving a large part of the shell may take several years to heal completely. Cagle (1945:45) reported that a bullet wound in the shell of a painted turtle (Chrysemys picta) healed completely in approximately 23 months. Danini (loc. cit.) found that regeneration of the shell in Emys orbicularis was complete in as short a time as 225 days. Woodbury and Hardy (loc. cit.) stated that small injuries to the shell of Gopherus agassizi may take as long as seven years to heal.

ECTOPARASITES

Two kinds of ectoparasites were found on ornate box turtles in the course of the present study; larvae of chigger mites (Trombicula alfreddugesi) were abundant on specimens collected in summer and, larvae of the bot fly (Sarcophaga cistudinis) were found on specimens throughout the season of activity, and, in a few instances, on hibernating turtles. In general, these ectoparasites do little or no harm to ornate box turtles, although heavy infestations may cause temporary interruption of normal activity or may even cause occasional death.

Concerning the larvae of T. alfreddugesi, Loomis (1956:1260) wrote, "In northeastern Kansas, larvae become numerous in early June (shortly after they first appear), increase in numbers to greatest abundance throughout late June and July, decrease slightly in August, become markedly reduced in September, and only a few larvae (mostly on hosts) remain in October and early November." He considered T. alfreddugesi to be the most abundant chigger mite in Kansas and stated (op. cit.:1265) that it is most common "… in open fields supporting good stands of grasses, weeds and shrubs, and where moderate to large populations of vertebrates are present." Loomis listed ornate box turtles (op. cit.:1261-2) as important hosts of Trombicula alfreddugesi but noted that box turtles are not so heavily infested as are certain other reptiles. The two other species of chigger mites that Loomis (op. cit.:1368) found on T. ornata in Kansas (T. lipovskyana and T. montanensis) were not found in the present study.

Box turtles were considered to have chigger infestations when the reddish larvae could be detected with the unaided eye. No chiggers were seen on turtles in the period from spring emergence until June 13, 1955. On the latter date a few scattered chiggers were noted on several individuals and it was on this same date that the writer received his first "chigger bites" of the year. Numbers of chiggers increased in the latter half of June and heavily infested turtles were noted throughout July. No chiggers were seen on box turtles after mid-September in 1955.

Chiggers were ordinarily found only on the soft parts of the turtles' bodies. Early in the season infestations were chiefly on the head and neck. Favorite sites of attachment were the point where the skin of the neck joins the carapace and on the skin around the eyes. Later in the season some chiggers could be found on nearly every part of the body where soft skin was present; concealed areas of skin, such as the axillary and inguinal pockets, the anal region, and the inner rim of the carapace (where it joins the skin of the body), harbored concentrations of chiggers. Juveniles were relatively more heavily infested than adults and, even early in the season, had chiggers attached along many of the interlaminal seams of the shell. Broad areas of soft, newly-formed epidermis on the shells of juveniles probably afforded a better place of attachment to chiggers than did the interlaminal seams of adults. The interlaminal seams and transverse hinges of adults were not infested until the height of the season of chigger activity. Heavily infested adults, observed in early July, were literally covered with chiggers; red larvae outlined nearly all the scutes of the shell, the anus, the mouth, and the eyes. When turtles were picked up for examination, chiggers could be seen moving rapidly from one interlaminal seam to another.

Box turtles kept in outdoor pens and in the laboratory did not long maintain visible infestations of chiggers, even during the time in summer when turtles found in the field were heavily infested.

A four-year-old juvenile was found nearly immersed in the shallow water of a pond on July 4, 1955; its right eye had been damaged by an especially heavy concentration of chiggers. When I released the turtle, some 50 feet from the pond, it returned to the water and spent the next four days there. The turtle was probably in a period of quiescence induced by the eye injury and the heavy infestation of chiggers; immersion in water could be expected to help free the turtle of chiggers and to relieve trauma resulting from the injured eye. Richard B. Loomis told me that larval chiggers are able to survive under water for several days but that warm water will hasten their demise.

Infestations of larval bot flies (Sarcophaga cistudinis) were noted in several turtles at the Damm Farm and, upon closer scrutiny, were found to be common in preserved specimens from other areas. Larvae were always found in flask-shaped pockets ([Pl. 27, Fig. 2]) beneath the skin; the pockets opened to the outside by a small hole, the edges of which were dried and discolored. One larva sometimes protruded from the opening. The inside of the pocket is lined with smooth, skinlike tissue. Heavily infested box turtles may have four or five such pockets, each containing one to many larvae. The most frequent sites of the pockets are the skin of the axillary and inguinal regions, and the skin of the limbs and neck, especially near the bases of these members. Subadults were more heavily infested than older adults; no infestations of hatchlings or small juveniles were noted.