The associations among performances, escape behaviour and sex have rarely been explored in animals. Dr. Yin Qi and his collaborators Martin Whiting, Daniel Noble have recently tested the links among escape behaviour, sex and locomotor performances in an agamid lizard Phrynocephalus vlangalii, see the abstract following (Doi: 10.1007/s00265-014-1809-5):
In lizards, males are predicted to sprint faster and run for longer than females by virtue of higher testosterone levels and differences in morphology. Consequently, escape behaviour is also predicted to be associated with sex and locomotor performance, yet these links have rarely been explored. Here, we tested whether escape behaviour is associated with locomotor performance in the toad-headed agama, Phrynocephalus vlangalii, and whether it is sex-dependent. This species is also characterized by elaborate tail displays, which we examined as a potential pursuit-deterrent signal. Tail waves were performed by a very small proportion (2/58, 3 %) of individuals during predatory trials, suggesting that tail signalling functions exclusively in a social context. To understand the relationships between sex, escape behaviour and performance, we first measured escape behaviour (flight initiation distance, flight distance—measured differently compared to previous studies of lizard escape behaviour, and refuge use) in the field before measuring maximal sprint speed and endurance on the same individuals in the laboratory. Flight initiation distance did not differ between the sexes and was unrelated to performance capacity (maximal endurance and sprint speed) but was positively related to body size with larger individuals fleeing earlier. Males fled farther than females, but flight distance was also unrelated to either endurance or sprint speed. Interestingly, faster females were less likely to enter a refuge than slower females, whereas sprint speed and the probability of taking refuge were unrelated for males. Our results suggest that when males and females are not obviously sexually dimorphic, they are more likely to overlap in escape tactics.
The movement based visual signals have been neglected long time but increasingly got much research with the development of 3D digitalizing and animation techniques. Many interesting questions, such as how and why motion signals vary? Are there specific condition-dependent motion signals? What is the function of each motion component? The Asian agamid genus Phrynocephalus became excellent systems for those questions, because both males and female this group made complex tail displays during social interactions, such as male-male competition, male courtship and female-female competition, even proportion of offspring display their tails in face to adults and other offspring. As the basic research for more complex design, we filed the tail display signals under different signal contexts, including male-male, male-female, female-female, offspring-male, offspring-female and offspring-offspring using two cameras, and the signal structure from each context would be quantified with 3D digitalizing methods. To understand the efficacy of each component, one 3D animation was also tested in the field. We would modify the present 3D animation with the collected videos. More pilot tests on the 3D animation would be carried out late this year. This work was finished by Dr. Yin Qi (Chengdu Institute of Biology, CAS), Dr. Richard Peters (La Trobe University, Australia), Jose Ramos, Yayong Wu.
As one important part of dynamic visual signal study, we visited the most high elevation toad-headed agamad Phrynocephalus theobaldi in Duilongdeqin county, 10 km west of Lhasa. Ke Jiang who will be our potential candidate master student accompanied me this time. Ke Jiang also found one of friend (Xiao Yang) in Lhasa helped us in the field. To be honest, both of us were a little worried about this trip, because one month ago, Ke Jiang had visited the same site and he found none active lizard during whole day. He suspected that this species might be very stationary and cryptic. Thus we had prepared many protocals for this field trip, such as waiting out of a burrow, digging and displacing lizard to a new site, or even putting focal lizard into enclosures, and so on.
The specific behavior of P. theobaldi changed our mind. As high elevation species, the display frequency was indeed smaller than other speices, such as P. frontillis and P. versicolor, and they seemed very timid and needed longer time to move out. But both of male and female lizards were very aggressive and territorial as P. vlangalii. When we tethered a male to focal male, the focal male would display immediately or even bite to the intruder. The most interesting point was that the focal male still made some courtship behaviors even we displaced focal lizard to a new site, this surprised us very much. We continued this work for one week, because there was a little raining every moring and we only had half a day for field work. The study on display of P. theobaldi means we had got all representive species of Genus Phrynocephalus finished and we would consider analyzing those data in next few monthes.
Working in south of Xinjiang Uyghur Autonomous Region is said to be risky. In general, Xinjiang is a nice place to live and visit, especially the northern part where cotton and fruit is plentiful. Nevertheless, southern Xinjiang is said to be little dangerous. In particular, the Kashi region which borders with some middle Asian countries and is traditionally a hotspot for terrorist activity. Killings and arson are the nightmares of local people and policemen. Thus, to do research in southern Xinjiang requires lots of courage (or stupidity). As a result, we restricted our activity to the north, which is a lot safer although while we were in the field there were attacks on police stations in a few small towns!
This years’ work is an important part of a big project we started last year on the evolution of dynamic visual signals in the lizard genus Phrynocephalus. Three Phrynocephalus species, including P.axillaris, P. forsythii and P. versicolor were on our hit list. All these species belong to different clades. Interestingly, P .forsythii’s ancestor lived in a high elevation area, but this species now lives at low elevation.The Takelama Gan Desert and Gobi Desert provide natural habitat for these species. Seeing the animals in the wild is always exciting for us and enables us to better understand their life history and also helps us come up with research questions for the future.
Four projects werecompleted during this field trip. First, we measured irradiance in the Tukai desert, near Huocheng, Yili city. This work will be used to study the flap signal function of Phrynocephalus mystaceus by Martin. Then, we collected the male-male and male courtship signals of P. axillaris near Ruoqiang, Bayingguole Mongalia Autonomous Region. This site was orignially planned for P. forsythii, but there was no longer any habitat as a result of local agriculture development when we arrived. We only found some remnant sand dunes, interspersed within large areas of cotton and jujube land. Luckily we found P.axillaris in some nearby gravel desert. To quickly collect data, we decided to do trials on P. axillaris in Ruoqiang. After Ruoqiang, we drove back to Yuli, where we had previously seen a few P. forsythii when we visited the week before. Our plan was to focus on P. forsythii in the field time we had left, but the risky conditions in Xinjiang stood in our way. We were not allowed to stay in Yuli because of local regulations that prevented westerners from staying over-night in the city because of so-called risks. And as it happened, we arrived on 5 July, which is the anniversary of a previous uprising that killed a lot of people. Our only option was to stay 47 km away in Kuerle if we wanted to work on P. forsythii. Given the commute to our field site and the level of security and general interference that we would have to put up with, we decided against it!.Therefore, we decided to drop P. forsythii for the moment and instead, to work on P. versicolor. The P. versicolor work was finished in Hami, which is 890 km away from Yuli through G314 and G30. Overall, we had an excellent field trip that involved a huge amount of driving (4380 km) and seeing some amazing lizards in the wild.
Behavior, ecology and evolution of reptiles and amphibians