Skolbekken R, Utne-Palm A C.
Department of Fisheries and Marine Biology, University of Bergen, PO Box 7800, N-5020, Bergen, Norway
J Exp Mar Biol Ecol. 2001 Jul 1;261(2):137-157. doi: 10.1016/s0022-0981(01)00249-0.
The trade-off between parental care and feeding was studied in the male two-spotted goby (Gobiusculus flavescens F.). Two temperatures, 8.5 degrees C and 13.0 degrees C, were used, with five replicates at each temperature, in order to determine whether temperature influenced parental behaviour. In each replicate, two males and four females were introduced to an aquarium, where the males chose between two nests and courted the females. In each replicate, one male spawned. After spawning, the males guarded the eggs until hatching. The guarding males' behaviour was recorded with a video camera twice a day (15 min each time), once before and once after they were fed. The male's condition (c-factor) was calculated at the start of the experiment and after egg hatching. The eggs were spawned in an artificial nest (half of a PVC tube), and attached to the nest in a single layer. The areas with eggs (representing brood size) were marked after spawning and the fry counted after hatching (which was used to calculate area hatched). Numbers of prey eaten (plankton) and number of aggressive encounters between the guarding male and the other fishes were recorded. Time spent in the nest and time used on fertilisation, fanning and cleaning were estimated and related to egg age, brood size, hatching success, temperature and food availability (no food or food).The results showed that feeding (expected to influence future reproduction) decreased and parental expenditure (current reproduction) increased, as the eggs developed (became closer to independence). Parental expenditure was significantly higher at 13.0 degrees C than at 8.5 degrees C, presumably due to higher oxygen demands by the eggs, and a greater risk of egg-infections. The c-factor of the males guarding eggs decreased over time, in contrast to the non-guarding males' c-factor. Guarding males' aggressiveness decreased as the eggs got older, but increased just before hatching. A possible explanation for this could be the decreasing intrusion by the non-guarding male and females caused by high aggressive behaviour by the guarding male early in the brood cycle. The exploitation of the nest (percentage of total nest area covered by eggs) seemed to determine the amount of parental expenditure and loss of condition, while brood size (area of eggs) had no effect.
在雄性双斑虾虎鱼（Gobiusculus flavescens F.）中研究了亲代抚育与觅食之间的权衡。实验采用了8.5摄氏度和13.0摄氏度两个温度，每个温度设置五个重复组，以确定温度是否会影响亲代行为。在每个重复组中，将两只雄性和四只雌性放入一个水族箱，雄性在两个巢穴之间进行选择并向雌性求偶。在每个重复组中，有一只雄性产卵。产卵后，雄性守护鱼卵直至孵化。用摄像机每天记录守护雄性的行为两次（每次15分钟），一次在喂食前，一次在喂食后。在实验开始时和鱼卵孵化后计算雄性的身体状况（c因子）。鱼卵产在一个人工巢穴（半根PVC管）中，并单层附着在巢穴上。产卵后标记有鱼卵的区域（代表育雏规模），孵化后清点幼鱼数量（用于计算孵化面积）。记录守护雄性吃掉的猎物数量（浮游生物）以及它与其他鱼类之间的攻击遭遇次数。估计雄性在巢穴中花费的时间以及用于受精、扇动和清洁的时间，并将其与鱼卵年龄、育雏规模、孵化成功率、温度和食物供应情况（无食物或有食物）相关联。结果表明，随着鱼卵发育（变得更接近独立），觅食（预期会影响未来繁殖）减少，亲代投入（当前繁殖）增加。13.0摄氏度时的亲代投入显著高于8.5摄氏度，可能是由于鱼卵对氧气的需求更高，以及鱼卵感染的风险更大。与未守护的雄性的c因子相比，守护鱼卵的雄性的c因子随时间下降。随着鱼卵变老，守护雄性的攻击性降低，但在孵化前增加。对此的一个可能解释是，在育雏周期早期，守护雄性的高攻击行为导致未守护的雄性和雌性的侵入减少。巢穴的利用率（鱼卵覆盖的总巢穴面积百分比）似乎决定了亲代投入的数量和身体状况的损失，而育雏规模（鱼卵面积）则没有影响。
