**6. Role of the turret**

*Ecosystem and Biodiversity of Amazonia*

**5. Moving the turret**

the exit of its well.

The reasons leading to the performance of this operation by the nymph remain to be elucidated because, during experiments of artificial lengthening of a turret by transplanting fragments from another one, a nymph does not manifest a requirement of a maximum height; in the long run, it accommodates a higher turret than the one it has built itself; it does not practice the technique which has just been described, nor any other. On the other hand, it ensures the sealing of the modified turret by plugging with soaked clay the interstices between the base of its turret and

This action of the nymph is rarely observed, but its peculiarity makes it worthy of presentation. A turret emerges near another which later tips over and lies down on the ground. The communication with the well is either completely closed or in the process of being sealed with clay (**Figure 11a**). The hypothesis can be put forward (**Figure 11b**) that the new turret is built over a deviation made by the nymph from

the implants received, in the same way as described above (**Figure 8**).

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**Figure 11.**

*(a) Spontaneous reconstruction of a new turret. (b) Diagram of deviation by the nymph of the outlet of the well:*  obt*: Filling with clay of the old outlet,* dfl*: Deviation made for a new outlet,* ft: *Former turret,* nt*: New turret.*

A correlation has been established [2] and confirmed later (Béguin, Gama and Ribamar Mesquita Ferreira, to be published) between the appearance of intense rains and the simultaneous temporary opening of the turrets at their top. A succession of 3 episodes, between July 19 and 23, 2016, turned out to be particularly significant; many openings (**Figure 12**) appeared, which were then closed when the precipitation stopped (**Figure 13**). The openings vary in shape, from a small hole about 5 mm in diameter (**Figure 12a**) to a larger opening where the contour of the clypeus, eyes or anterior part of the pronotum (**Figure 12b**) can frequently

#### **Figure 12.**

*(a) Circular orifice resulting from a slight pressure of the mass of soggy clay against the wall of the summit. (b) Orifice with imprint of clypeus (cly) and pronotum (pro) covered with soggy clay. (c–f) occlusion of the orifice shown in Figure 12a after end of rainfall, by injection of soggy clay (captured images with the automatic camera* Brinno timelapseTLC200 Pro*).*

#### **Figure 13.**

*Correlation between intense rainfalls (////) and temporary and simultaneous opening of 35 turrets, during 3 episodes, between July 19 and 23, 2016.*

be observed, as a consequence of the liquefaction of the clay from the top wall by applying these parts covered with clay wet with urine. After the rain has stopped, the nymph closes these openings by injecting moist clay (**Figure 12c**–**f**).

When rainfalls are heavy, the soil becomes very wet and the moisture level in the burrow increases dramatically. In addition, rainwater in some places passes through a rapidly decomposing litter [3]. We can therefore imagine that the level of CO2 also increases. The temporary opening of the turret would therefore lower these rates, as well as the concomitant increase in pressure. *The turret would thus appear as a regulating device of the physical–chemical conditions prevailing inside the burrow*.
