{
  "id": 10711422,
  "title": "How host self-regulation governs hyperparasitoid persistence in a caterpillar-parasitoid-trigonalid system",
  "url": "https://urgent.news/2026/09/29/how-host-self-regulation-governs-hyperparasitoid-persistence-in-a",
  "topic": "science",
  "section": "Science",
  "published": "2026-09-29T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.09.28.755095v1?rss=1"
  },
  "original_language": "en",
  "account": "Species at the highest trophic level are often the most vulnerable to disturbances. However, the factors that enable their persistence remain unclear. The study investigates how an organism's intrinsic self-regulation influences the stability of higher trophic levels. To explore this, the researchers use a simplified model of a host-parasitoid-hyperparasitoid system based on trigonalid wasps, which are hyperparasitoids that develop only when their caterpillar host is also targeted by a primary parasitoid. Two models of host self-regulation are compared: scramble fecundity, where the parasitoid is the primary threat, leading to classical Beddington and Hammond dynamics; and contest fecundity, where the host is controlled by multiple enemies. Through numerical analysis and model trajectory calculations, the results show that the type of host regulation plays a crucial role in maintaining stability at the top trophic level. When hosts exhibit scramble dynamics, coexistence becomes highly sensitive to changes in parameters and initial conditions. In contrast, contest dynamics result in more stable coexistence, even under broader parameter ranges. The transition to chaos occurs gradually through a supercritical Neimark-Sacker bifurcation and subsequent torus-doubling. Consequently, the stability of top levels in certain food webs may be influenced by the self-regulation mechanisms present at the base of the network.",
  "summary": "Species at the highest trophic levels are generally the least resilient to perturbations, yet the factors that determine their persistence remain poorly understood. We ask how the intrinsic self-regulation of a basal host governs the persistence of the trophic levels above it. To address this question, we use a minimal discrete-time model of a host-parasitoid-hyperparasitoid system motivated by…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}