Philomatry in plants: why do so many species have limited seed dispersal?

Abstract

Many have noted limited seed dispersal of plants in diverse environments and attempted evolutionary explanations for it. Although philopatric (“love of fatherland”) is used by zoologists to describe organisms that remain near their place of origin, philomatric (“love of motherland”) is proposed as more appropriate for plants because seeds develop on the maternal parent, fecundity and dispersal are maternally influenced characteristics, and the term dovetails with the mother‐site hypothesis (MSH) for the evolution of restricted dispersal. Proximate reasons for philomatry include intrinsic drivers such as morphological features of diaspores and where on the maternal parent they are produced. Extrinsic drivers include local environmental conditions, surrounding vegetation, and ineffective dispersal agents. The MSH proposes that selection should favor philomatry in a population adapted to a particular habitat because offspring will likewise be adapted to that same habitat. Several studies show philomatry can mitigate distance‐dependent costs of dispersing into surrounding inhospitable areas. Undispersed diaspores can eliminate energetic costs of accessory structures or biochemicals needed by dispersible diaspores, but it is unclear whether these costs are significant to the evolution of philomatry. Disadvantages of limited dispersal are inability to escape deteriorating habitat conditions, inability to colonize new habitats, and inbreeding among offspring. Heterocarpic species offset these disadvantages by producing dispersed plus undispersed diaspores. A conceptual framework is presented relating dispersal distance to the probability of seedling establishment. Future research should recognize dispersal as a covarying syndrome of multiple life history traits and focus on ecological selection agents that favor philomatry.

Anchorage by seed mucilage prevents seed dislodgement in high surface flow: a mechanistic investigation

“…Across plants, particularly from desert or ruderal environments, extremely limited dispersal is a common phenomenon, which likely decreases seed loss to unsuitable habitats (Ellner & Schmida, 1981). Cheplick (2022) termed this limited dispersal from mother plants “philomatry” and differentiates extrinsic (mostly environmental) and intrinsic (mostly plant characters) drivers. Anchorage by seed mucilage prevents dislodgement (Garcia-Fayos et al, 2013, Engelbrecht et al, 2014), and therefore can be considered an intrinsic driver of philomatry.…”

“…Anchorage by seed mucilage prevents dislodgement (Garcia-Fayos et al, 2013, Engelbrecht et al, 2014), and therefore can be considered an intrinsic driver of philomatry. Dispersal, or anti-dispersal, traits are often part of broader syndromes correlated with other life- history traits across plants (Cheplick, 2022). The presence and amount of mucilage has broader correlates, including ruderal life-histories (Grubert, 1974, Ryding, 2001), and being more pronounced in warmer areas with high solar radiation (Pan et al, 2021).…”

“…Additionally, it is reasonable, though as of yet untested, that these same traits contribute more to other functions: dislodgement force of wet mucilage probably drives epizoochorous dispersal (Ryding, 2001), a slower mucilage decay rate may increase survival of seeds through the gut of herbivores (Kreitschitz et al, 2021a), and faster imbibition rate could lead to better DNA repair during brief wetting periods (Huang et al, 2008). These all may thus be part of a syndrome of life-history traits that species with mucilaginous seeds largely share and possibly account for their similar ecological niches (Grubert, 1974), a result that may suggest a mucilaginous life-history syndrome, of which limited dispersal is just one component (à la Cheplick, 2022).…”

“…Dispersal, or anti-dispersal, traits are often part of broader syndromes correlated with other lifehistory traits across plants (Cheplick, 2022). The presence and amount of mucilage has broader correlates, including ruderal life-histories (Grubert, 1974, Ryding, 2001, and being more pronounced in warmer areas with high solar radiation (Pan et al, 2021).…”

“…These all may thus be part of a syndrome of life-history traits that species with mucilaginous seeds largely share and possibly account for their similar ecological niches (Grubert, 1974), a result that may suggest a mucilaginous life-history syndrome, of which limited dispersal is just one component (à la Cheplick, 2022).…”