Dietary source for skin alkaloids of Dendrobatid poison frogs

Žabe porodice Dendrobatidae sadrže otrovne alkaloide u kožnim žlijezdama. Dugo se smatralo da ih same sintetiziraju, no istraživanjem je dokazano kako su alkaloidi ipak porijeklom od malih člankonožaca kojima se hrane. Vršena su istraživanja koja bi dokazala teoriju o postanku alkaloida iz prehrane. To je uključivalo uzgoj žaba u kavezu u kojemu su vinske mušice bile jedini izvor prehrane. U tim uvjetima pronađeno je vrlo malo alkaloida. Uzgoj u kavezu sa svježim lišćem sakupljenim iz njihovog izvornog staništa, dalo je drugačiji profil alkaloida. Žabe sakupljene iz prirodne okoline, naravno, sadržavale su sve alkaloide koje ta vrsta inače sadrži. No one koje su uzgajane u staklenom terariju, potpuno izolirane od okoline, nisu sadržavale otrovne alkaloide. Ovakav je ishod pokusa bio i za očekivati uz postavljenu hipotezu i prijašnja istraživanja. Žabe ove porodice većim dijelom koriste mrave u prehrani. Istraživanja su uključivala različite vrste ove porodice, a njima se htjela naći poveznica između njih i mrava porodice Formicidae preko raznih spojeva pumiliotoksina koristeći plinsku kromatografiju i masenu sprektrometriju. Istraživanja su pokazala kako mravi rodova Brachymyrmex i Paratrechina sadrže navedene spojeve. Prisutnost pumiliotoksina u ovim mravima, kao i u ekstraktima kože Dendrobates pumilio, zajedno s pronalaskom B. depilis u želucima ovih žaba, definitivno može stajati kao dokaz da ove žabe koriste navedene mrave kao izvor prehrane i pumiliotoksina. Prema dobivenim rezultatima može se zaključiti sljedeće: prisutnost člankonožaca uvjetuje pojavu alkaloida. A njihova koncentracija i raznolikost ovisi o raspoloživosti plijena. Aposemija je pojava za koju se smatra da se razvija zajedno s pojavom otrovnosti, a komparativnim je analizama utvrđena veza između obojenosti i otrovnosti jedinki. Upravo im je ta otrovnost omogućila dnevni način života i bezbrižno kretanje bez brige od napada predatora, a sposobnost sakupljanja otrovnih alkaloida iz organizama kojima se hrane, učinila ih je veoma uspješnom skupinom životinja.Dendrobatid frogs contain a variety of poisonous alkaloids in the skin glands. These alkaloids were initially considered to be synthesized by these frogs, but later studies showed they were actually of dietary origin. There were many research efforts to test the dietary hypothesis. Such work included placing frogs into outdoor cage with a diet of only fruit flies. The occurrence of alkaloids in skin extracts from these captive-raised frogs was very low. Another group of captive-raised frogs placed in outdoor screened cage, but provided with fresh leaf litter gathered from the area where these frogs were common, showed different alkaloid profile. And as expected, wild-caught frogs contained all alkaloids known to that species. Frogs raised in large glass terrarium, isolated entirely from natural surroundings, had no detectable alkaloids in the skin extracts. All of the results were as expected from previous studies and consistent with a given hypothesis. Dendrobatid frogs consume a high proportion of ants as part of their diet in the wild. Using gas chromatographic-mass spectral analysis, many tests were made on a variety of dendrobatid frog species to find a connection between formicine ants and these frogs. That connection was found in the presence of pumiliotoxins in both groups. Pumiliotoxins were detected in ants of the genera Brachymyrmex and Paratrechina. The presence of pumiliotoxins in these ants as well as in skin extracts of the dendrobatid frog Dendrobates pumilio, coupled with the presence of these ants in stomach contents of Dendrobates pumilio, strongly suggests that these ants represent a dietary source for pumiliotoxins in these populations of frogs. Based on results of all research it can be said that arthropods are the source of poison alkaloids in dendrobatid frogs and that their amount and variety is determined only by the availability of those arthropods in their environment. A comparative approach was used to test a prediction of the hypothesis of aposematism: coloration will evolve in tandem with toxicity. And it's the combination of two that allows them to have a diurnal lifestyle and to live carelessly, freed from any fear of predation. This made them to be very successful and well adapted species

Dietary source for skin alkaloids of Dendrobatid poison frogs

Žabe porodice Dendrobatidae sadrže otrovne alkaloide u kožnim žlijezdama. Dugo se smatralo da ih same sintetiziraju, no istraživanjem je dokazano kako su alkaloidi ipak porijeklom od malih člankonožaca kojima se hrane. Vršena su istraživanja koja bi dokazala teoriju o postanku alkaloida iz prehrane. To je uključivalo uzgoj žaba u kavezu u kojemu su vinske mušice bile jedini izvor prehrane. U tim uvjetima pronađeno je vrlo malo alkaloida. Uzgoj u kavezu sa svježim lišćem sakupljenim iz njihovog izvornog staništa, dalo je drugačiji profil alkaloida. Žabe sakupljene iz prirodne okoline, naravno, sadržavale su sve alkaloide koje ta vrsta inače sadrži. No one koje su uzgajane u staklenom terariju, potpuno izolirane od okoline, nisu sadržavale otrovne alkaloide. Ovakav je ishod pokusa bio i za očekivati uz postavljenu hipotezu i prijašnja istraživanja. Žabe ove porodice većim dijelom koriste mrave u prehrani. Istraživanja su uključivala različite vrste ove porodice, a njima se htjela naći poveznica između njih i mrava porodice Formicidae preko raznih spojeva pumiliotoksina koristeći plinsku kromatografiju i masenu sprektrometriju. Istraživanja su pokazala kako mravi rodova Brachymyrmex i Paratrechina sadrže navedene spojeve. Prisutnost pumiliotoksina u ovim mravima, kao i u ekstraktima kože Dendrobates pumilio, zajedno s pronalaskom B. depilis u želucima ovih žaba, definitivno može stajati kao dokaz da ove žabe koriste navedene mrave kao izvor prehrane i pumiliotoksina. Prema dobivenim rezultatima može se zaključiti sljedeće: prisutnost člankonožaca uvjetuje pojavu alkaloida. A njihova koncentracija i raznolikost ovisi o raspoloživosti plijena. Aposemija je pojava za koju se smatra da se razvija zajedno s pojavom otrovnosti, a komparativnim je analizama utvrđena veza između obojenosti i otrovnosti jedinki. Upravo im je ta otrovnost omogućila dnevni način života i bezbrižno kretanje bez brige od napada predatora, a sposobnost sakupljanja otrovnih alkaloida iz organizama kojima se hrane, učinila ih je veoma uspješnom skupinom životinja.Dendrobatid frogs contain a variety of poisonous alkaloids in the skin glands. These alkaloids were initially considered to be synthesized by these frogs, but later studies showed they were actually of dietary origin. There were many research efforts to test the dietary hypothesis. Such work included placing frogs into outdoor cage with a diet of only fruit flies. The occurrence of alkaloids in skin extracts from these captive-raised frogs was very low. Another group of captive-raised frogs placed in outdoor screened cage, but provided with fresh leaf litter gathered from the area where these frogs were common, showed different alkaloid profile. And as expected, wild-caught frogs contained all alkaloids known to that species. Frogs raised in large glass terrarium, isolated entirely from natural surroundings, had no detectable alkaloids in the skin extracts. All of the results were as expected from previous studies and consistent with a given hypothesis. Dendrobatid frogs consume a high proportion of ants as part of their diet in the wild. Using gas chromatographic-mass spectral analysis, many tests were made on a variety of dendrobatid frog species to find a connection between formicine ants and these frogs. That connection was found in the presence of pumiliotoxins in both groups. Pumiliotoxins were detected in ants of the genera Brachymyrmex and Paratrechina. The presence of pumiliotoxins in these ants as well as in skin extracts of the dendrobatid frog Dendrobates pumilio, coupled with the presence of these ants in stomach contents of Dendrobates pumilio, strongly suggests that these ants represent a dietary source for pumiliotoxins in these populations of frogs. Based on results of all research it can be said that arthropods are the source of poison alkaloids in dendrobatid frogs and that their amount and variety is determined only by the availability of those arthropods in their environment. A comparative approach was used to test a prediction of the hypothesis of aposematism: coloration will evolve in tandem with toxicity. And it's the combination of two that allows them to have a diurnal lifestyle and to live carelessly, freed from any fear of predation. This made them to be very successful and well adapted species

Dietary source for skin alkaloids of Dendrobatid poison frogs

Žabe porodice Dendrobatidae sadrže otrovne alkaloide u kožnim žlijezdama. Dugo se smatralo da ih same sintetiziraju, no istraživanjem je dokazano kako su alkaloidi ipak porijeklom od malih člankonožaca kojima se hrane. Vršena su istraživanja koja bi dokazala teoriju o postanku alkaloida iz prehrane. To je uključivalo uzgoj žaba u kavezu u kojemu su vinske mušice bile jedini izvor prehrane. U tim uvjetima pronađeno je vrlo malo alkaloida. Uzgoj u kavezu sa svježim lišćem sakupljenim iz njihovog izvornog staništa, dalo je drugačiji profil alkaloida. Žabe sakupljene iz prirodne okoline, naravno, sadržavale su sve alkaloide koje ta vrsta inače sadrži. No one koje su uzgajane u staklenom terariju, potpuno izolirane od okoline, nisu sadržavale otrovne alkaloide. Ovakav je ishod pokusa bio i za očekivati uz postavljenu hipotezu i prijašnja istraživanja. Žabe ove porodice većim dijelom koriste mrave u prehrani. Istraživanja su uključivala različite vrste ove porodice, a njima se htjela naći poveznica između njih i mrava porodice Formicidae preko raznih spojeva pumiliotoksina koristeći plinsku kromatografiju i masenu sprektrometriju. Istraživanja su pokazala kako mravi rodova Brachymyrmex i Paratrechina sadrže navedene spojeve. Prisutnost pumiliotoksina u ovim mravima, kao i u ekstraktima kože Dendrobates pumilio, zajedno s pronalaskom B. depilis u želucima ovih žaba, definitivno može stajati kao dokaz da ove žabe koriste navedene mrave kao izvor prehrane i pumiliotoksina. Prema dobivenim rezultatima može se zaključiti sljedeće: prisutnost člankonožaca uvjetuje pojavu alkaloida. A njihova koncentracija i raznolikost ovisi o raspoloživosti plijena. Aposemija je pojava za koju se smatra da se razvija zajedno s pojavom otrovnosti, a komparativnim je analizama utvrđena veza između obojenosti i otrovnosti jedinki. Upravo im je ta otrovnost omogućila dnevni način života i bezbrižno kretanje bez brige od napada predatora, a sposobnost sakupljanja otrovnih alkaloida iz organizama kojima se hrane, učinila ih je veoma uspješnom skupinom životinja.Dendrobatid frogs contain a variety of poisonous alkaloids in the skin glands. These alkaloids were initially considered to be synthesized by these frogs, but later studies showed they were actually of dietary origin. There were many research efforts to test the dietary hypothesis. Such work included placing frogs into outdoor cage with a diet of only fruit flies. The occurrence of alkaloids in skin extracts from these captive-raised frogs was very low. Another group of captive-raised frogs placed in outdoor screened cage, but provided with fresh leaf litter gathered from the area where these frogs were common, showed different alkaloid profile. And as expected, wild-caught frogs contained all alkaloids known to that species. Frogs raised in large glass terrarium, isolated entirely from natural surroundings, had no detectable alkaloids in the skin extracts. All of the results were as expected from previous studies and consistent with a given hypothesis. Dendrobatid frogs consume a high proportion of ants as part of their diet in the wild. Using gas chromatographic-mass spectral analysis, many tests were made on a variety of dendrobatid frog species to find a connection between formicine ants and these frogs. That connection was found in the presence of pumiliotoxins in both groups. Pumiliotoxins were detected in ants of the genera Brachymyrmex and Paratrechina. The presence of pumiliotoxins in these ants as well as in skin extracts of the dendrobatid frog Dendrobates pumilio, coupled with the presence of these ants in stomach contents of Dendrobates pumilio, strongly suggests that these ants represent a dietary source for pumiliotoxins in these populations of frogs. Based on results of all research it can be said that arthropods are the source of poison alkaloids in dendrobatid frogs and that their amount and variety is determined only by the availability of those arthropods in their environment. A comparative approach was used to test a prediction of the hypothesis of aposematism: coloration will evolve in tandem with toxicity. And it's the combination of two that allows them to have a diurnal lifestyle and to live carelessly, freed from any fear of predation. This made them to be very successful and well adapted species

Reproductive characteristics of the viviparous lizard (Zootoca vivipara Lichtenstein)

Živorodna gušterica, Zootoca vivipara Lichtenstein 1823 ima najveći areal rasprostranjenja od svih gmazova, ali njena je rasprostranjenost na na području Republike Hrvatske i Bosne i Hercegovine slabo poznata. Zbog toga je napravljena nova karta distribucije ove vrste. Živorodna gušterica jedina je unutar porodice Lacertidae koja ima dva načina razmnožavanja, oviparni i ovoviviparni. Proučavane su dvije populacije: jedna s planine Vlašić (BIH; pripada podvrsti Zootoca vivipara vivipara Von Jacquin, 1787) i druga iz šume Spačva (RH; smatra se da pripada podvrsti Zootoca vivipara pannonica Lac & Kluch, 1968). Kako bih utvrdila njihovu reproduktivnu strategiju, sakupila sam gravidne ženke i držala ih u terariju sve do izlijeganja mladih. Bilježila sam promjene mase ženki prije i poslije polijeganja jaja, te masu i veličinu jaja i tek izleglih mladunaca. Istraživanje je pokazalo da veće ženke imaju veća legla i veće i teže potomstvo, dok rezultati t-testa pokazuju da oviparne ženke imaju veća legla, veću srednju masu i srednje SVL vrijednosti mladunaca.Viviparous lizard, Zootoca vivipara Lichtenstein 1823 is wide-distributed reptile but data on it’s distribution in Croatia and Bosnia and Herzegovina is scanty. It is the only lacertid lizard with two modes of reproduction, oviparous and ovoviviparous. Two geographically distinct populations were studied. One from Vlašić (BIH; Zootoca vivipara vivipara Von Jacquin, 1787 subspecies) and other from Spačva (CRO; considered to be Zootoca vivipara pannonica Lac & Kluch, 1968). Gravid females were collected from sampling sites, to establish their reproductive mode. They were put into terraria until juveniles hatched. Data on female body mass change (before and after oviposition and parturition respectively), size and mass of both eggs and hatchlings were taken. Population from Vlašić was ovoviviparous while population from Spačva was oviparous. This research also proved heavier and bigger females to have larger clutch size and hatchlings with larger SVL size and bigger mass. Results obtained from t-test showed that that oviparous females have larger clutch size and hatchlings with bigger average SVL size and average body mass