Insights into the Interaction between the Monophagous Tephritid Fly Anastrepha acris and its Highly Toxic Host Hippomane mancinella (Euphorbiaceae).

Despite their enormous economic importance and the fact that there are almost 5000 tephritid (Diptera) species, fruit fly - host plant interactions are poorly understood from a chemical perspective. We analyzed the interactions among Anastrepha acris (a little studied monophagous tephritid) and its highly toxic host plant Hippomane mancinella from chemical, ecological and experimental perspectives, and also searched for toxicants from H. mancinella in the larval-pupal endoparasitoid Doryctobracon areolatus. We identified 18 phenolic compounds from H. mancinella pulp belonging to different chemical groups including phenylpropanoids, flavonoids, chalcones and coumarins. No traces of Hippomanin A were detected in larvae, pupae or A. acris adults, or in D. areolatus adults, implying that A. acris larvae can metabolize this toxicant, that as a result does not reach the third trophic level. We tested the "behavioral preference - lack of larval specialization-hypothesis" via feeding experiments with a larval rearing medium containing H. mancinella fruit (skin + pulp or pulp alone). The high toxicity of H. mancinella was confirmed as only two (out of 2520 in three experiments) A. ludens larvae (a polyphagous pest species that preferentially feeds on plants within the Rutaceae) survived without reaching the adult stage when fed on media containing H. mancinella, whereas A. acris larvae developed well and produced healthy adults. Together, these findings open a window of opportunity to study the detoxification mechanisms used by tephritid fruit flies.

Severity of manchineel fruit (Hippomane mancinella) poisoning: A retrospective case series of 97 patients from French Poison Control Centers.

In this retrospective series of 97 cases of manchineel fruit ingestion reported to French Poison Control Centers between 2009 and 2017, we investigated cases of poisoning due to manchineel fruit (from the Hippomane mancinella tree). This fruit is known to be responsible for oropharyngeal and gastrointestinal tract lesions and possibly hypotension and bradycardia (previously attributed to the presence of physostigmine). The most commonly observed clinical signs were oropharyngeal pain, abdominal pain, diarrhea and oropharyngeal irritation. No major gastrointestinal tract lesions were observed in the five cases in which upper gastrointestinal (GI) endoscopy was performed. One case of laryngeal edema and one case of bradycardia were observed, but analysis of the harvested fruits did not confirm the presence of physostigmine. Ingestion of manchineel fruit can cause mild abdominal pain and digestive irritation, requiring medical attention. Rarely, when several fruits have been ingested, severe oropharyngeal injury or hemodynamic disorders may require otorhinolaryngological consultation or cardiac monitoring for several hours, respectively.

[A recrute with blisters on the cheek]. / Een militair met blaren op de wang.

A 37-year-old recrute in the Royal Dutch Army developed blisters on the right cheek approximately 30 minutes after a boot camp exercise in the mangroves of the island of Curaçao. This bullous dermatitis was caused by direct contact with sap from the bark of the manzanilla tree (Hippomane mancinella). As a member of the family Euphorbiaceae, all parts of this tree are highly toxic. Even rain drops falling from the leaves can cause a bullous dermatitis. Usually, symptomatic treatment will allow healing of the dermatitis in a matter of weeks.

Conspecific plasticity and invasion: invasive populations of Chinese tallow (Triadica sebifera) have performance advantage over native populations only in low soil salinity.

Global climate change may increase biological invasions in part because invasive species may have greater phenotypic plasticity than native species. This may be especially important for abiotic stresses such as salt inundation related to increased hurricane activity or sea level rise. If invasive species indeed have greater plasticity, this may reflect genetic differences between populations in the native and introduced ranges. Here, we examined plasticity of functional and fitness-related traits of Chinese tallow (Triadica sebifera) populations from the introduced and native ranges that were grown along a gradient of soil salinity (control: 0 ppt; Low: 5 ppt; Medium: 10 ppt; High: 15 ppt) in a greenhouse. We used both norm reaction and plasticity index (PIv) to estimate the conspecific phenotypic plasticity variation between invasive and native populations. Overall, invasive populations had higher phenotypic plasticity of height growth rate (HGR), aboveground biomass, stem biomass and specific leaf area (SLA). The plasticity Index (PIv) of height growth rate (HGR) and SLA each were higher for plants from invasive populations. Absolute performance was always comparable or greater for plants from invasive populations versus native populations with the greatest differences at low stress levels. Our results were consistent with the "Master-of-some" pattern for invasive plants in which the fitness of introduced populations was greater in more benign conditions. This suggests that the greater conspecific phenotypic plasticity of invasive populations compared to native populations may increase invasion success in benign conditions but would not provide a potential interspecific competitive advantage in higher salinity soils that may occur with global climate change in coastal areas.

Manchineel dermatitis in North American students in the Caribbean.

We report an outbreak of Manchineel dermatitis and ophthalmitis in four students from North America who visited the island of Bequia, West Indies. The exposure resulted from taking shelter during a rain storm under a Manchineel tree. Manchineel exposure and ingestion can lead to severe and even fatal disease.

Dermatitis por Toxicodendron striatum (manzanillo) / Dermatitis caused by Toxicodendron striatum (manzanillo)

Se describe y discute el caso de un paciente que presenta dermatitis de contacto por exposición al árbol conocido en algunos sectores de la región andina de Colombia como “manzanillo” de nombre científico Toxicodendron striatum o Rhus striata. Pertenece la familia de las anacardiáceas, plantas vasculares que producen savia con gran contenido de principios activos. El agente desencadenante del daño es el urushiol, una mezcla de ortobencenodioles alquilados o catecoles alquilados, saturados o insaturados. Es un aceite incoloro o amarillo claro, presente en las hojas, el tallo y la raíz de la planta. El cuadro se inicia con eritema, edema, vesiculación y pápulas, llegando en ocasiones a formar ampollas que pueden ser muy extensas. No se limitan al sitio del contacto sino que se generalizan al resto de la piel con mayor compromiso de los pliegues. Esta dermatitis es muy frecuente en Estados Unidos por el contacto con plantas pertenecientes al mismo género, Toxicodendron, conocidas como plantas venenosas (hiedra venenosa, poison ivy, roble venenoso, poison oak y zumaque venenoso, poison sumac). El mecanismo de lesión inducido por urushiol es eminentemente inmunológico, aunque al referirse a estas dermatitis se habla de dermatitis por plantas venenosas o dermatitis venenata, como si se tratara de una dermatitis de contacto irritativa. En Centro y Sur América las dermatitis por T. striatum son muy conocidas y temidas por los campesinos y personas que trabajan en los bosques.El tratamiento recomendado es lavar con abundante agua y jabón en las primeras cuatro horas después del contacto así como lavar todos los objetos contaminados. Los medicamentos no acortan el curso de la enfermedad de manera importante. Las lesiones desaparecen en una a dos semanas. El interés del tema está en que los clínicos se familiaricen con la entidad, conozcan el mecanismo de lesión y entiendan la importancia de la educación para el control de esta enfermedad.