Biology subjects

Cenzer, M.

Publications and source records attributed to Cenzer, M..

3 recordsLinked to original sources

bioRxiv2022

Dispersal-behavioral plasticity within an insect-host system undergoing human-induced rapid environmental change (HIREC)

As environments change, often drastically, due to human activities, dispersal-behavioral plasticity can become a key mediator of metapopulation connectivity and the interactions between an individual and its altered environment. Our goal was to investigate the traits and ecological processes that affect plastic dispersal responses within an insect-host system undergoing human-induced rapid evolutionary change (HIREC). Since the 1960s, populations of the red-shouldered soapberry bug from Florida, USA, originally feeding on the seeds of Cardiospermum corindum on the islands, quickly adapted to feeding on an invasive, ornamental tree, Koelreuteria elegans, on the mainland, which led to host-specific wing polyphenism. Here, we measured the morphology of >3,500 soapberry bugs field collected from 2013 to 2020 and the flight performance of 378 total soapberry bugs tested in a flight mill during Fall 2019 and Winter 2020. Flight tests showed females and mainland natives exhibited variable flight responses mediated by mass, while males were consistent, wing-dependent flyers. However, historical specimens showed annual rises in flightless morphs for males and dwindling wing-to-body sizes for island natives since 2013. Despite uncertain future fitness consequences, plasticity could help predict mobility character and agent dispersal behavior and ultimately help identify whether recent trends signal adjustment or maladaptation to HIREC.

ecology↗

bioRxiv2017

Adult facilitation becomes competition as juvenile soapberry bugs age

Whether intraspecific interactions are facilitative or competitive may change across individual ontogeny. In plant-feeding insects, the direction of this interaction is likely to be mediated by host plant defenses. Here I conducted two experiments looking at the direct effect of a physical seed defense and the role of intraspecific facilitation in reducing the effects of that defense for juveniles. I first demonstrate that juveniles of the red-shouldered soapberry bug (Jadera haematoloma) are severely inhibited by the tough seed coat of their host plant, leading to high mortality early in development. Adults, in contrast, can create holes through which other individuals could potentially feed. I then manipulated whether or not seeds experienced adult feeding on two host plant species: a well-defended native host, balloon vine (Cardiospermum corindum) and a poorly defended introduced golden rain tree species (Koelreuteria elegans). I measured the effect of prior adult feeding on survival, development time, and final body size of soapberry bug juveniles. Survival in the first week of development was dramatically improved by prior adult feeding on both hosts. However, the benefits of prior adult feeding ceased after the first week of development and shifted to having a negative effect on performance. These results indicate that adults breaking through the seedcoat initially facilitate juveniles, but that this facilitation becomes competition as juveniles age.

ecology↗

bioRxiv2016

Natural selection and maladaptive plasticity in the red-shouldered soapberry bug

Natural selection and phenotypic plasticity can both produce locally differentiated phenotypes, but novel environments or gene combinations can produce plasticity that works in opposition to adaptive change. The red-shouldered soapberry bug (Jadera haematoloma) was locally adapted to feed on the seeds of an introduced and a native host plant in Florida in the 1980s. By 2014, local differentiation was lost and replaced by phenotypically similar populations all adapted to the introduced host, likely as a result of gene flow. Here, I quantify the effects of these two host plants on individual performance, natural selection, and phenotypic plasticity. I find that the seed coat and seedpod of the native host have strong negative effects on juvenile survival and adult reproduction compared to the introduced host. I find support for the hypothesis that the seedpod is driving diversifying natural selection on beak length, which was previously locally adapted between hosts. I also find maladaptive plasticity induced by host plant: bugs develop beak lengths that are mismatched with the seedpod size of the host they are reared on. This plasticity may be the result of gene flow; hybrids in the 1990s showed the same pattern of maladaptive plasticity, and plasticity is stronger in the present in areas with high gene flow. Although ongoing natural selection has produced locally adapted genotypes in soapberry bugs, maladaptive plasticity has masked the phenotypic difference between populations in the field.

evolutionary biology↗