A Ponder of Western toads

[BlacklightHunter]

Hello, I have a few Q’s about some western toad larva that I saved from a drying up pool. I live in San Diego and with our recent rain we got some perennial pools in which the local westerns propagated in. unfortunately the pools dried up but not before I could save several thousand of them. I have some questions though about what I observed.
The main large pool was formed from the largest rainstorm we’ve had in ten years, yet it dried up before any of the tadpoles could fully develop. How can they continue to propagate with that survival rate?
I also observed that most of the tadpoles (for lack of a better word) were the typical blackish-brown color while about 2% of them were stark white with gold dust. They all have exactly the same body structure and mouth parts. What is the difference here between the two drastic color morphs? Will they keep that color into adulthood?
What’s more, I found another pool about a mile away (far enough away with hills and thick bushes which would prevent toads from pool-hopping) which might last long enough for the tadpoles in it to finish their metamorphosis, but all I could find in that one were the stark white tadpoles.
Lastly, at the large pool I also found pacific chorus frogs! This place in in the middle of chaparral for miles with no lasting water source. I thought that chorus frogs needed a continual water source. Can they hibernate like the western toads?
Thank you for slogging through my post, and any answers will be appreciated!

[John]

Refreshingly interesting questions that I believe I can answer:

The main large pool was formed from the largest rainstorm we’ve had in ten years, yet it dried up before any of the tadpoles could fully develop. How can they continue to propagate with that survival rate?

This is the survival game that explosive breeders play. Really dry ground that receives a downpour often won't hold the water for long due to cracking and overall huge porosity (the degree to which it will absorb water or let it pass through). It varies with soil type and consistency, but often with dry soils like what you've probably seen there, they need a gentle or mild rain a few days before the heavy rain falls, in order to reach the right consistency to hold a lot of water. The amphibians don't know that though and they often have to take what chances come their way. In many species of toad that breed like this, not all of the females will lay during the first storm, particularly if it's early in the year. They're the ones that help ensure there are successful "crops" of toadlets even when most of the other toads made a bad laying decision. Still, most amphibian populations can go a year or two without recruitment of juveniles, so all is not lost.

I also observed that most of the tadpoles (for lack of a better word) were the typical blackish-brown color while about 2% of them were stark white with gold dust. They all have exactly the same body structure and mouth parts. What is the difference here between the two drastic color morphs? Will they keep that color into adulthood?

It's unlikely they'll keep that into adulthood. I've seen colour variety in the tadpoles of some US toad species in the wild. Unless it's a true colour mutation, it's likely a way for the toads to hedge their bets regarding light versus water temperature - a dark tadpole will absorb a lot of heat from the sun, which will speed its metabolism and likely lead to metamorphosis sooner (perhaps at a bigger or smaller size). The lighter tadpoles may have a slower rate of metabolism but that might present advantages in the event of a lower abundance of food. This is educated speculation. Presence or lack of predators may also be factors.

What’s more, I found another pool about a mile away (far enough away with hills and thick bushes which would prevent toads from pool-hopping) which might last long enough for the tadpoles in it to finish their metamorphosis, but all I could find in that one were the stark white tadpoles.

Assuming they're not a different species, that might speak to my hypothesis in the last answer. It's quite normal for toads to prefer very temporary pools over those that last longer - fewer predators to eat the tadpoles, but they risk the pool not lasting so long. Also, some toads prefer certain types of temporary pool - I've seen this quite a bit where Great Plains Toads and Woodhouse's Toads overlap in Oklahoma - they'll breed at the same time after a storm, but rarely share the same breeding pool - Woodhouse's prefer ditches and GPTs prefer shallow pans in fields (which are often relict buffalo wallows).

Lastly, at the large pool I also found pacific chorus frogs! This place in in the middle of chaparral for miles with no lasting water source. I thought that chorus frogs needed a continual water source. Can they hibernate like the western toads?

I would imagine that Pacific Chorus Frogs can find refuges, perhaps not in the same manner as toads (digging down), but the fact that you're seeing them breed means that they have found some moist refuge to survive the drought.

[BlacklightHunter]

awesome answers! thank's so much. I'm still curious as to what the white ones will look like compared to the "normal" black ones.

[John]

awesome answers! thank's so much. I'm still curious as to what the white ones will look like compared to the "normal" black ones.

You're very welcome - it's nice to have interesting questions instead of "my tree frog is sick, help!!" for a change :P.

Provided it's legal (I believe it's alright to collect a few Bufo boreas tadpoles in California), collect some and raise them. Perhaps they'll turn out an interesting colour but I doubt it.

[Kurt]

Collect them and raise them up.

[Ron]

Bufo boreas...hands down my favorite amphibian EVER. I believe down there you have the subspecies B. b. halophilus. Just a couple things to add:

Pseudacris regilla don't need year-round water to survive (the classifiers keep going back and forth as to whether or not they should be a "chorus" frog or a "tree" frog). As long as they can stay somewhere damp, they should be okay.

If you decide to raise up any toadlets/froglets, I would HIGHLY recommend not raising them in or near any other non-native or tropical species in order to prevent cross-contamination of possible foreign parasites and pathogens...which could then be inadvertently introduced into the local environment when you release them.

[BlacklightHunter]

Just an update, I’ve been active on Field Herp Forums and they’ve answered all my Q’s. The tadpoles turned out to be Spea hammondii (Wstern Spadefoot toads). This was beyond my dreams as these are a threatened species and very hard to find! I’ve only seen them on occasion at the Wild Animal Park while doing field research there. It’s hard to believe that I have 2,000 + in my own tank! Don’t worry about cross-contamination, I’m being as carfull as CRES to keep these guys away from chitrid. The white ones that I mentioned turned out to be the first recored albino hammondii! I have a friend of mine who’s a head researcher at SDZICR who’s coming over on Saturday to photgraph and take some of them to include in the next edition of his Field Guide To Amphibians and Reptiles of the San Diego Region.

[Kurt]

Cool. I hope that you do post some pictures.

[BlacklightHunter]

here's the whole story with pictures:

http://www.fieldherpforum.com/forum/...hp?f=5&t=29792

[John]

Pity we got no picture love here .

[Kurt]

I love the albinos. Really cool.