Turtle Meetings and Matings and Gene Flow
In their research paper "How Do Male Box Turtles Find Mates?", William R. Belzer and Susan Seibert state:
"None of the findings ..(in their controlled laboratory environment)..... provide evidence that male eastern box turtles can use long-range cues to find potential mates."
"That circumstance suggests that high habitat residency is needed to enable multiple annual matings and multipaternity. Multipaternity may make important contributions (e.g., increased number of eggs, clutch fertility, hatching success, or neonate vitality) that sustain chelonian populations."
"If short-range visual stimuli are critical for bringing potential box turtle mates together, then as population density declines, mating opportunities and population recruitment also decline, or even vanish, long before the population has disappeared."
--So evidently, male eastern box turtles need to see a female before they will court and mate.--
....but that certainly doesn't sound good for a wild local population of this size and density. There must be more to it than that. Most of the new turtles I have radio-tagged in this study area, have been found while meeting or mating with turtles already being tracked.
These males and females do find each other in this mountainous terrain, even with long travel distances, short sight distance, and many large obstacles. With a maximum eye height of only 4 or 5 inches, a few ferns or a fallen tree would block any motion detection of a turtle even very close by. Meetings appear to be much more than just chance encounters.
Some of these turtles travel long distances outside their primary activity areas, and consequently intersect other turtles' activity areas. Most of these turtles seem (obviously) to be intimately familiar with their areas of travel, and are not randomly moving about. It seems possible, or maybe even likely, that turtles remember previous meetings and mating locations from the past.
There are also places that I call "meeting areas" where turtles of the opposite or same sex are often observed together. These are not necessarily within either turtle's primary activity area, or an overlap of the same, but to meet in one of these areas, both (or sometimes three) turtles necessarily have to be at the same place at the same time. Is this chance occurrance or planning?
Box turtles meet for reasons other than mating. Males, in particular, are regularly found sitting together, usually on the ground, shell to shell, but occasionally one on top of the other. This is not mock mating nor is it aggression: there is little if any movement, but must be some sort of communication. Male/Male pairs participate in this activity, and possibly Female/Female also, although this has never yet been observed at this site.
Turtles travel long distances and straight line routes to meet. Many new turtles have been found by tracking tagged turtles who are meeting others.
This photo is of M13 on top of M8, both tagged males, that I have followed for many years. This is how they were found, and they remained in this position most of the day.
This is a graphical representation (sociogram) of the actual (observed) gene flow among turtles in this population. Each arrow represents one or more meetings or matings over 15 years tracked. Higher numbered turtles are more recent finds and most were found while mating or meeting with already tagged turtles.
The fear of the spread of evolving diseases through abandoned pet turtles is a serious issue.
A virus would likely travel along the same lines. In 2012 a possible abandoned pet box turtle, (M27) with it's carapace painted white, was found by a maintenance worker in a parking area within my study area, and was moved into the woods so he did not get run over. He was found 2 seasons later meeting with M51(m), and has been track since.
The left side of the chart shows male/male meetings, including those with transients that may move among many local populations. Females are almost never found meeting another female, even though several females are occasionally found in a same small area.
It has been suggested that this is territorial behavior, but I have never yet observed any aggressive behavior between any of these turtles.
"Turtles have a far greater sense of smell than even the famed bloodhound. Every sense of the turtle is beyond the capacity of any other animal on the planet. However, turtles cannot hear very well as they are missing an eardrum."
"Box turtles have a good sense of smell, which they use to help them find food, mates and territory."
"Do box turtles have a sense of smell?"
"Yes, itís one of their strongest senses. They use their sense of smell to find delicious food and locate water miles away."
"16. Can box turtles smell well?"
"Yes, box turtleís have a very strong sense of smell. Because they are slow moving they must use their sense of smell to sense food and predators before they encounter them and thus require a keen sense of smell."
Sense of Smell The following are exact (cut and paste) quotes from several web page search results from Googling "Box turtle sense of smell". I have yet to find any published research to confirm these statements, but I suspect that Box turtles do have a well developed sense of smell, as well as sight. I am not necessarily suggesting that smell is a primary way for turtles to find each other (or food resources, or nesting site soils, etc.) ............
Always Under Construction
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