Love vine sucks life from wasps, leaving only mummies


Early this spring, Rice University evolutionary biologist Scott Egan stood in a patch of live oak scrub habitat in South Florida and scanned the trees for something he’d never seen outside his lab — a wispy, orange vine twining itself around swollen stems or pea-sized growths on the underside of oak leaves.

Rice University bioscientists have discovered the first example of a parasitic plant attacking a parasitic insect on a shared host plant. Cassytha filiformis, also known as love vine, feeds off of galls, the natal chambers of parasitic wasps.

Egan needed visual confirmation of something he and his students noticed in the lab a few months earlier: love vine, a parasitic plant, latching onto and feeding off of not the tree itself, but the tumor-like growths made by his favorite insects, gall wasps.

“I went to spots where I knew that my gall-formers and the vines were, and I just blurred my eyes across the tops of the trees,” Egan said, re-enacting the moment he scanned the forest. “And, once you have seen it, you can’t not see it. I’m like, ‘Oh. It’s everywhere. I can’t not find it, on this branch, or on this one or this one.”

For Egan, who has spent 17 years studying gall-forming insects and logged thousands of miles collecting samples from oak forests across a dozen U.S. states, it was a revelation.

“I had never seen this,” Egan said. “But the fact that no one, as far as we know, had ever documented this was incredible because biologists have studied each of these — the vines and the insects — for more than a century.”

In ecological parlance, the find was a new trophic interaction between two species, meaning that one was feeding off the other. “Basically, you have a parasitic plant attacking a parasitic insect inside of another host, a host they share,” he said.

read more…source

Paper:
Botanical parasitism of an insect by a parasitic plant

An orchid matches its scent rhythm to the locals

Interesting, white flowers are white to attract pollinators at night, several orchids I’ve owned have a scent that is very strong after dark but barely there during the day.

We find that the floral scent of the orchid Gymnadenia conopsea differs between day and night, and the increase in scent from day to night is stronger in populations with nocturnal pollination. This is the first study to report genetic variation in floral scent emission rhythms within the same species, and this is an important first step to understand the evolution of floral scent.

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Diel pattern of floral scent emission matches the relative importance of diurnal and nocturnal pollinators in populations of Gymnadenia conopsea

Yes, some plants do use camouflage


…. But a review by scientists from the University of Exeter and the Kunming Institute of Botany (Chinese Academy of Sciences) found plants use a host of techniques long known to be used by animals.

These include blending with the background, “disruptive colouration” (using high-contrast markings to break up the perceived shape of an object) and “masquerade” (looking like an unimportant object predators might ignore, such as a stone).

“It is clear that plants do more than entice pollinators and photosynthesise with their colours—they hide in plain sight from enemies too,” said Professor Martin Stevens, of the Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall.

“From ‘decoration’, where they accumulate things like dust or sand on their surface, to disruptive coloration, they use many of the same methods as animals to camouflage themselves.

“We now need to discover just how important a role camouflage has in the ecology and evolution of plants.”

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Exeter Press Release

Plants pass climate data onto children

Plants integrate seasonal signals, including temperature and day length, to optimize the timing of developmental transitions. Seasonal sensing requires the activity of two proteins, FLOWERING LOCUS C (FLC) and FLOWERING LOCUS T (FT), that control certain developmental transitions in plants. During reproductive development, the mother plant uses FLC and FT to modulate progeny seed dormancy in response to temperature. We found that for regulation of seed dormancy, FLC and FT function in opposite configuration to how those same genes control time to flowering. For seed dormancy, FT regulates seed dormancy through FLC gene expression and regulates chromatin state by activating antisense FLC transcription. Thus, in Arabidopsis the same genes controlled in opposite format regulate flowering time and seed dormancy in response to the temperature changes that characterize seasons. paper $$

Mother knows best — how plants help offspring by passing on seasonal clues

FLOWERING LOCUS C (FLC) regulates development pathways throughout the life cycle of Arabidopsis

Plant mothers talk to their embryos via the hormone auxin

Can plants think?

“Plant-thinking” refers, in the same breath, to (1) the non-cognitive,
non-ideational, and non-imagistic mode of thinking proper to plants (hence,
what I call “thinking without the head”); (2) our thinking about plants; (3)
how human thinking is, to some extent, de-humanized and rendered plantlike,
altered by its encounter with the vegetal world; and finally, (4) the
ongoing symbiotic relation between this transfigured thinking and the
existence of plants. A sound philosophy of vegetal life must rely on the
combination of these four senses of “plant-thinking,” so as not to dominate
(and in dominating, distort) the target of its investigations. In this article, I
will touch upon all four senses of plant-thinking, putting particular accent
on its first and last modalities. Upon investigating the non-conscious
intentionality of plants and how it resonates with the human thinking of
non-identity, I will draft the image of Western philosophy as a sublimated
and idealized plant-thinking. more …

Are Plants Conscious?
Plant-Thinking: A Philosophy of Vegetal Life

Touch your plants and they’ll tell their neighbors

Yearly tree pruning

Plants can detect the presence of their neighbours and modify their growth behaviour accordingly. But the extent to which this neighbour detection is mediated by abiotic stressors is not well known. In this study we tested the acclimation response of Zea mays L. seedlings through belowground interactions to the presence of their siblings exposed to brief mechano stimuli. Maize seedling simultaneously shared the growth solution of touched plants or they were transferred to the growth solution of previously touched plants. We tested the growth preferences of newly germinated seedlings toward the growth solution of touched (T_solution) or untouched plants (C_solution). The primary root of the newly germinated seedlings grew significantly less towards T_solution than to C_solution. Plants transferred to T_solution allocated more biomass to shoots and less to roots. While plants that simultaneously shared their growth solution with the touched plants produced more biomass. Results show that plant responses to neighbours can be modified by aboveground abiotic stress to those neighbours and suggest that these modifications are mediated by belowground interactions.

rest of the paper