Data from: Investigating movement in the laboratory: dispersal apparatus designs and the red flour beetle, Tribolium castaneum

The natural dispersal of Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) has been emulated
in the laboratory for more than 50 years, using a simple dispersal apparatus. This has typically comprised
of a starting container (initial resource or patch) connected by tubing, which contains thread
for the animals to climb into a tube and hence to an end container. That is, beetles move to a new
viable resource or patch from an inter-patch zone or non-viable habitat. We modified this basic
apparatus design to test the effect of tubing length and tubing insertion angle on the dispersal rate
and proportion of successful dispersers. We expected that the proportion of successful dispersers
would be repeatable within each apparatus design, and that increasing tubing length and steepness of
the insertion angle would reduce dispersal rate and success across apparatus designs. Dispersal
increased linearly through time, similarly so for both males and females. The design with the most
vertical tubing insertion angle had a lower proportion of successful dispersers. Tubing length also
had a negative relationship with dispersal success (as judged by insects reaching the end container),
but a significant reduction in dispersal success was only apparent between the shortest and longest
tubing between containers. We suggest that locating and climbing the vertical section of string before
they can enter the tubing between containers restricts dispersal and that at higher densities, insects
exhibit greater inclination to climb. This type of apparatus has flexible design tolerances and further
potential to study the dispersal of other small insect species that primarily use pedestrian locomotion.

五十余年来，科研人员已借助简易扩散装置在实验室中模拟了赤拟谷盗（Tribolium castaneum Herbst，鞘翅目（Coleoptera）：拟步甲科（Tenebrionidae））的自然扩散行为。该装置通常由起始容器（初始资源斑块）与连接管路构成，管路内置供昆虫攀爬的丝线，使昆虫可经由管路进入末端容器。换言之，甲虫会从斑块间区域或非适宜生境，迁移至新的可利用资源斑块。
本研究对该基础扩散装置的结构进行改造，以探究管路长度与管路插入角度对扩散速率及成功扩散个体占比的影响。我们提出两项假设：其一，同一装置设计下，成功扩散个体的占比具备可重复性；其二，增加管路长度与插入角度的陡峭程度，会降低不同装置设计下的扩散速率与扩散成功率。
扩散强度随时间呈线性增长，雌雄个体均呈现一致规律。管路插入角度最接近垂直的装置，其成功扩散个体的占比更低。管路长度与扩散成功率（以成功抵达末端容器的昆虫数量为衡量标准）呈负相关，但仅在容器间最短与最长管路组之间，扩散成功率的下降才达到显著水平。
我们推测，昆虫在进入容器间管路前，需先定位并攀爬竖直丝线段，这一过程限制了扩散行为；而当种群密度较高时，昆虫的攀爬意愿会显著增强。这类扩散装置具备较高的设计容错性，且可进一步用于探究其他主要依靠步行运动的小型昆虫的扩散行为。