McConnell Nathan J, Rohner Patrick
Department of Ecology, Behavior, and Evolution, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
J Exp Biol. 2025 Aug 15;228(16). doi: 10.1242/jeb.251022. Epub 2025 Aug 19.
Organisms are not just passive recipients of environmental pressures but can shape the environment they experience. Yet, the mechanisms and evolutionary implications of such niche construction remain poorly understood. Here, we studied these effects in the gazelle dung beetle (Digitonthophagus gazella). Larvae of this species develop in an underground brood chamber (a 'brood ball') composed of dung, which serves as the sole source of food for a single larva. Throughout its development, the larva extensively modifies its environment by constantly eating, regurgitating and shaping particle sizes within the brood ball. Previous research suggests that these larval manipulations increase environmental quality and nutrient availability. However, how larval modifications affect larval growth and how these modifications differ between species remain poorly understood. We studied the impact of larval environmental modifications by transplanting eggs into previously modified or unmodified environments, whilst controlling for the confounding effect of maternally derived microbes. Additionally, we also studied how D. gazella larvae grow in an environment that was modified by a different species (Onthophagus binodis) to investigate species-specific differences of niche construction. Counter to expectations, we found that larval modifications by conspecifics did not confer a fitness benefit to D. gazella. However, surprisingly, individuals developing in a brood ball modified by a heterospecific individual emerged significantly quicker. These findings provide mixed support that environmental modifications by a larva enhance its growth. Our research adds to the growing literature on the complex interactions between organisms and their environment and how those interactions feed back on organismal development and performance.
生物体并非仅仅是环境压力的被动承受者，它们还能够塑造自身所处的环境。然而，这种生态位构建的机制及其进化意义仍知之甚少。在此，我们以瞪羚蜣螂（粪金龟属）为研究对象，探究了这些影响。该物种的幼虫在由粪便构成的地下育雏室（“育雏球”）中发育，这是单个幼虫唯一的食物来源。在整个发育过程中，幼虫通过持续进食、反刍以及塑造育雏球内的颗粒大小，对其环境进行了广泛的改造。先前的研究表明，这些幼虫的行为提高了环境质量和养分可利用性。然而，幼虫的改造如何影响其生长，以及这些改造在不同物种之间存在怎样的差异，目前仍不清楚。我们通过将卵移植到先前已改造或未改造的环境中，同时控制母源微生物的混杂效应，研究了幼虫对环境改造的影响。此外，我们还研究了粪金龟幼虫在由另一个物种（双瘤嗡蜣螂）改造的环境中的生长情况，以探究生态位构建的物种特异性差异。与预期相反，我们发现同种个体的幼虫改造并未给粪金龟带来适应性优势。然而，令人惊讶的是，在由异种个体改造的育雏球中发育的个体出现得明显更快。这些发现为幼虫对环境的改造能促进其生长这一观点提供了喜忧参半的支持。我们的研究进一步丰富了关于生物体与其环境之间复杂相互作用，以及这些相互作用如何反馈于生物体发育和表现的文献。
