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MidWest Frogs Gerhardt-Scramble Competition“Well, the wood frogs breed explosively and so they probably are calling at most, for three or four nights at the peak. So they’re relying completely on stored energy to do that from the winter. They’re probably using as much energy jostling around, swimming around the pond because they call but they’re also just try to grab anything that moves. So they’re doing, what’s called scramble competition. So they’re calling but there’s not much evidence in frogs like that that the female is really using the sound very much for localizing the male, or that she even initiates the mating. She goes into that pond and usually gets grabbed. And in fact a lot of her choice might be on how she might actually try to kick off a male that’s too small, for example. What happens then, of course, is she may not have to do that because a larger male may come along and knock off that smaller guy anyway. But in the case of the spring peeper, the males are calling from one place for most of the night, and for many nights and so they have to sustain a tremendous amount of energetic cost for their breeding season. And so, they rely on some stored energy as well, but they are also doing a little bit of feeding. Because I mean, they’re going to have a breeding season that lasts as much as two months. In things like wood frogs where they are doing scramble competition they really prefer larger females cause they've got more eggs and so... But mostly it’s the females that make the choice."
Gerhardt - Treefrog Choice “So when a male gray tree frog calls for three or four hours the aerobic metabolic rate is going up something like twenty times resting. It’s really the equivalent of running a marathon. And they’re doing this night after night for a long season. And so, it’s an indicator for the physical, energetic cost that this male is investing in his courtship. So this could be something useful for the female, especially if only the fittest males were able to sustain this energetic cost for a very long time. Well, it turns out in gray tree frogs, at least we can show that in fact the female gets something from this choice. Because they do prefer males that give longer than average calls. So we collected males, who were producing longer than average calls and we were especially looking for males that were producing shorter than average calls. And we took a series of females and we divided their clutches and we fertilized the eggs with the sperm of long calling males and, with the sperm of short calling males. And then we looked at the viability of the tadpoles and we found, in fact, that the offspring of the long calling males grew faster and grew larger and metamorphosed, that is became little frogs sooner than the offspring of the short calling males. Clearly, the males with the longer calls that were showing, in fact, that they were physically fit also had some genetic fitness which the female was able to benefit from."
Gerhardt - Communication/Evolution “Communication is central to evolutionary biology because you’ve got to get the sexes together because you have senders that are producing the signals and receivers who are receiving and acting on those signals. And they exert selective pressure on each other. So signalers that don’t get it right don’t get mated or don’t chase off rivals effectively and receivers that are too picky don’t find any, don’t find mates. Or if they’re not picky enough they get bad mates."
Gerhardt- How it Started “Whenever there’s some energy that’s produced by one animal that gets detected by another animal and it changes that other animal’s behavior then you can say that’s communication so… animals make incidental sounds probably from locomotion or breathing or, you know, snapping shells or whatever and if that was correlated with some information about that that the receiver could use then that’s probably how communication got started. Or, for example, in the animals I work with, frogs, sometimes when the frog jumps in the water it expels air and makes a sound and that could have been the start for some acoustic communication."
Gerhardt – Sound Communication “Sound seems to be mysterious because we don’t see it, they’re just sound waves and yet it can convey an enormous amount of information. The signal tells me what species it is, it tells me that it’s a male, it tells me that it’s a reproductively active male, and if it’s a species where there’s good correlations with between body size and pitch, it can tell me whether it’s a small male or a large male. Sound has a big advantage of being able to produce signals without tying up appendages or legs and arms so you can, animals can run away and still be communicating by sound. Another advantage is that sound unlike light can go around obstacles like trees, it’s very good in the forest, it works day and night. Sound is one of the most efficient long distance signals. The cricket frog, I’ve measured the peak amplitude at 110 decibels at a distance of fifty centimeters. That is a very short sound but they build up the energy, then the larynx opens and the vocal chords vibrate for just, for a few milliseconds at this peak amplitude of 110 db, which is pretty loud."
Gerhardt – Frog Repertoires “The usual call that you’re hearing, scientists refer to as advertisement calls. They used to be termed mating calls. And they have that function, that is, they do attract females for mating. But advertisement is a more general term because this signal also is influencing nearby males. So if males are interacting vocally before fighting and one is, say, getting too close to the other one then he will switch to a second kind of call. And they’re called encounter calls, or they’re called aggressive calls.
Lannoo - Malformed Frogs “There are a number of causes for malformed frogs, ranging from pesticides and other sort of harmful chemicals, retnoic acid, the wrinkle cream that you put on your face to prevent from having crows feet to augmented natural biological phenomenon. And so when you have increased nutrient input into wetlands, you have increased plant matter, and then you have increased snail populations in response to the increased plants and these snails are an intermediate host for a parasite that’s known to infect frogs and cause malformations. And so in some wetland systems just by adding more nutrients, more food for plants, what comes out at the end is malformed frogs. We did a survey two summers ago of the hottest of the hot spots and what we found was all of the hot spots were altered wetlands. They all had problems. And to our way of thinking if you want to solve the malformed frog problem, you’ve got to restore these wetlands.”
Lannoo - Declining Amphibian Populations “The biggest amphibian decline issue that we have in the Midwest has been the mysterious decline of cricket frogs in the upper Midwest. They are extirpated from Canada, they’re extirpated from Minnesota, they’re gone from most of their historic area in Wisconsin, in Michigan, they’re gone from the northern portion of Iowa, most of the northern portion of Illinois and Indiana and parts of Ohio in the north also. Cricket frogs are thought to only live about eighteen months. And so what that means is that they have to breed every year regardless of conditions. And if you have a prolonged drought and you have habitat loss, or habitat fragmentation such that they can’t get from what was a good habitat but isn’t now to what will be a good habitat because there are barriers or roads, subdivisions or whatever. They can’t make the historical trek, migration over to the better wetland. And so it may be that one factor involved with cricket frog declines is that not every place that has always had cricket frogs can support cricket frogs in every year."
Karen Glennemeier, Ph.D - Audubon, Frog Monitoring“I’m Karen Glennemeier and I work for Audubon of the Chicago region. And we coordinate the Chicago Wilderness Habitat project, which is a coalition of about 150 groups. And they created what’s called the biodiversity recovery plan. Which is a brilliant document that lays out all of the natural treasures of this region, what the biggest threats to the treasures are and what we need to do about it. An ecosystem is a web of life and we can’t possibly monitor and measure every single piece of that web. So we pick the things that are easiest and give us the most information and have the most potential for enriching our lives in the process. And so frogs are ideal for that, and they also are like many other animals good indicators of how the habitat is doing. So if there’s a real problem with the water quality, you might see it in the frog population. They’re really charismatic. And they’re pretty easy to learn. We only have thirteen species in the region. You learn them by their calls, which in most cases, they’re easy to hear and easy to distinguish once you learn them. You know, who wouldn’t be delighted by that sound? And when you get a frog monitor out for the first time listening to this, it just opens up a whole new world that they didn’t know existed. Once they start monitoring they start really understanding what’s going on in the wetland. And they start thinking about what’s good for the frogs. I had a monitor call me last week about a town meeting, about spraying for mosquitoes. Saying “is this going to effect the frogs? What should I say at the meeting?” and so we talked about that. So people are definitely becoming more sophisticated about ecosystem function, and ecosystem preservation than they were before the monitoring. And I think it’s the citizen scientists that give me hope because, you know, that this program is effecting hundreds of people and they’re each effecting a couple of people. And one person can’t do it alone. That’s why we have this network of people. And people who really care at a very fundamental level about these animals.”
Brodman - Seasonal Strategies “We’re in Jasper county in northwest Indiana and we’re at this marsh on the first warm day of late winter. And this habitat is a great place to monitor amphibians. The kinds of amphibians that typically come to these ponds are going to be animals that spend their life up on land and then come to the water to lay their eggs and and develop. In the woods we’re going to have species coming out including the spring peeper and the blue spotted salamander. Out in the fields we’re going to have species coming in like chorus frogs, northern leopard frogs and the tiger salamander. Wetlands like these are very valuable to certain species of animals like frogs and salamanders because it’s deep enough that it’ll hold water through the spring into summer so that their eggs can develop and their tadpoles can develop. But it will often dry up in the summer or in the winter freeze to the bottom and this is important because it keeps fish out. When you have a deeper body of water like a lake or a pond, the fish come in and they’re natural predators on the amphibians. We have some species that come out at this time of the year, March, early April, when the temperatures are getting above 45 degrees in the night time. And then as spring warms up and we start getting evenings where it’s 55 degrees then another wave of species will come out of hibernation and start breeding. And finally in the summer when the temperatures are in the evening getting above 65 degrees then we have our last wave of species coming in. One advantage of coming out early is that you can exploit that resource before other species do. But on the other hand, the advantage of breeding a little bit later is with warmer temperature you can grow faster. With warmer temperature you don’t run the risk of freezing. The species that breed first, they’re at the risk that if we get another cold snap and the pond freezes over that their eggs could freeze. So you have one advantage at being out early but a disadvantage associated with it. And it’s the balance between those two that that works out best for each species.”
Brodman - Wetland Diversity"A lot of people when they think about biodiversity, they think of a tropical rainforest and all of the species that live there. But in places like the Midwest, we have pockets of very high biodiversity as well, very high productivity. And these are the wetlands, wetlands are the most productive ecosystem on the planet. More productive than the tropical rainforest and coral reefs. Yet these are a resource that have been under assault for the last century. Historically, this area would have been primarily wetlands and also savanna habitat, a mixture of forested areas with open prairie areas. Over time in the last hundred years much of the wetlands have been drained and filled to create farmland and also for urban development and residential homes and such. When we look at a wetland like this, some people see it as “oh, it’s just a swamp, it’s not productive land”. But as far as the wildlife are concerned, this is the most productive spot that we’re going to find. When we look at the number of amphibians that that are going be growing in here, the number of insects that they’re feeding upon, the number of birds that will come visit the pond and prey upon those amphibians. We’re seeing a tremendous amount of biodiversity being produced right here from this wetland.
Beasley - Cricket Frog Declines “Envirovet is a program that we started in 1991, And what we try to do is to show the veterinarian that he can use the same approaches in many ways that the wildlife biologist does to bring his expertise to wildlife issues as well.
When I’m trying to describe what a veterinarian offers to the community of wildlife biology or ecology, I always use the analogy of biochemistry and medicine. Val Beasley, DVM, PhD, DABVT
Maglia - The Frog SkeletonThere’s a lot of things about frogs that make them particularly suited for looking at skeletal evolution because frogs have a really interesting and unique skeleton. My primary interest is in evolution and, specifically, looking at how development plays a role in the evolution. But I also look at trying to understand evolutionary history in different group and trying to recreate that history. To understand how different frogs are related to one another.
Maglia - Frog SpeciationWe know that this proto-frog, Triadobatrachus, was likely Pangean. So we know this is very early during the time when we had this big super continent, about 240 million years ago roughly. Gondwanaland was when you took this big Pangaea continent and split it in half, half of it went north and became North America and Europe. And the other half went south and that became South America and Africa and India. And as Gondwanaland, this southern continent, started breaking up into pieces and parts different frogs evolved on these different pieces and parts. So, Gondwanaland seems to be where a lot of our frogs evolved.
Aguti - Ugandan Frogs Uganda is a very, very good place for Herpetology. I'm a Herpetologist. Herpetology is the study of reptiles and amphibians…. Due to limited expertise in Herpetology we only have, so far, ninety-eight amphibian species recorded in Uganda.
When there was a scholarship that was advertised in my University and they wanted somebody to write a concept about amphibians and then I sat for the interview…I got the scholarship. My interest in Herpetology basically developed when I was already an adult. Each time that I am walking around, I'm very keen, I'm always looking on the ground because I'm very sure an amphibian must be jumping…even on the road or I'm in the car, I very look…I'm always looking out for amphibians. There's no direct value that people get from amphibians, so they don't see that amphibians are indicators of environmental change. Uganda is ahead of the other countries in terms of wetland management but it is only that the poverty levels here are really too high that sometimes when the people encroach the wetlands, it is because they are trying to earn a living. The wetlands have been degraded. So, it is because of the human activities locally here in Uganda that has led to the change of the weather patterns here. Rain does not come as it used to before. Evapotranspiration that takes place here in these wetlands is very, very low or it is non-existent at all. But now I'm very glad that we can go out to the schools and interest the young peoples in the schools to go out into the site of the frogs…that would work. If we could really get more funding to go into these areas, I think more work would be done, we would discover more species, we would discover ecological factors that could be effected several diverse amphibians and species richness in Uganda.
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