Department of Biology and Ecology, Faculty of Science, University of Ostrava, Ostrava, Czech Republic.
PLoS One. 2011;6(7):e21987. doi: 10.1371/journal.pone.0021987. Epub 2011 Jul 21.
Marine sponges are frequently inhabited by a wide range of associated invertebrates, including caridean shrimps. Symbiotic shrimps are often considered to be commensals; however, in most cases, the relationship with sponge hosts remains unclear. Here we demonstrate that sponge-inhabiting shrimps are often parasites adapted to consumption of sponge tissues. First, we provide detailed examination of morphology and stomach contents of Typton carneus (Decapoda: Palaemonidae: Pontoniinae), a West Atlantic tropical shrimp living in fire sponges of the genus Tedania. Remarkable shear-like claws of T. carneus show evidence of intensive shearing, likely the result of crushing siliceous sponge spicules. Examination of stomach contents revealed that the host sponge tissue is a major source of food for T. carneus. A parasitic mode of life is also reflected in adaptations of mouth appendages, in the reproduction strategy, and in apparent sequestration of host pigments by shrimp. Consistent results were obtained also for congeneric species T. distinctus (Western Atlantic) and T. spongicola (Mediterranean). The distribution of shrimps among sponge hosts (mostly solitary individuals or heterosexual pairs) suggests that Typton shrimps actively prevent colonisation of their sponge by additional conspecifics, thus protecting their resource and reducing the damage to the hosts. We also demonstrate feeding on host tissues by sponge-associated shrimps of the genera Onycocaris, Periclimenaeus, and Thaumastocaris (Pontoniinae) and Synalpheus (Alpheidae). The parasitic mode of life appears to be widely distributed among sponge-inhabiting shrimps. However, it is possible that under some circumstances, the shrimps provide a service to the host sponge by preventing a penetration by potentially more damaging associated animals. The overall nature of interspecific shrimp-sponge relationships thus warrants further investigation.
海洋海绵经常栖息着各种各样的相关无脊椎动物，包括十足目虾类。共生虾通常被认为是共生体；然而，在大多数情况下，与海绵宿主的关系仍然不清楚。在这里，我们证明了栖息在海绵中的虾类通常是适应消耗海绵组织的寄生虫。首先，我们详细检查了生活在 Tedania 属火海绵中的西大西洋热带虾 Typton carneus（十足目：对虾科：Pontoniinae）的形态和胃内容物。T. carneus 的惊人的剪切状爪子表明它具有强烈的剪切作用，这可能是由于压碎硅质海绵刺的结果。对胃内容物的检查表明，宿主海绵组织是 T. carneus 的主要食物来源。寄生的生活方式也反映在口附属物的适应、繁殖策略以及虾对宿主色素的明显隔离上。西大西洋的同种 T. distinctus 和地中海的 T. spongicola 也得到了一致的结果。虾类在海绵宿主中的分布（主要是单独的个体或异性对）表明 Typton 虾类积极防止其海绵被其他同种虾类定植，从而保护它们的资源并减少对宿主的损害。我们还证明了海绵共生虾属 Onycocaris、Periclimenaeus 和 Thaumastocaris（Pontoniinae）和 Synalpheus（Alpheidae）的虾类对宿主组织的摄食。寄生的生活方式似乎在栖息在海绵中的虾类中广泛分布。然而，在某些情况下，虾类通过防止潜在更具破坏性的相关动物穿透，为宿主海绵提供服务，这是有可能的。因此，种间虾-海绵关系的总体性质值得进一步研究。
