During this time, the once hotter universe began to cool and matter clumped together, forming the first stars and galaxies. As these stars and galaxies emerged, their energy heated the surrounding environment, reionizing some of the remaining hydrogen in the universe.

The universe’s reionization is well known, but determining how it happened has been tricky. To learn more, astronomers have peered beyond our Milky Way galaxy for clues. In a new study, astronomers at the University of Iowa identified a source in a suite of galaxies called Lyman continuum galaxies that may hold clues about how the universe was reionized.

In the study, the Iowa astronomers identified a black hole, a million times as bright as our sun, that may have been similar to the sources that powered the universe’s reionization. That black hole, the astronomers report from observations made in February 2021 with NASA’s flagship Chandra X-ray observatory, is powerful enough to punch channels in its respective galaxy, allowing ultraviolet photons to escape and be observed.

“The implication is that outflows from black holes may be important to enable escape of the ultraviolet radiation from galaxies that reionized the intergalactic medium,” says Phil Kaaret, professor and chair in the Department of Physics and Astronomy and the study’s corresponding author.

“We can’t yet see the sources that actually powered the universe’s reionization because they are too far away,” Kaaret says. “We looked at a nearby galaxy with properties similar to the galaxies that formed in the early universe. One of the primary reasons that the James Webb Space Telescope was built was to try to see the galaxies hosting the sources that actually powered the universe’s reionization.”

Jesse Bluem, a graduate research assistant at Iowa, and Andrea Prestwich, with the Harvard-Smithsonian Center for Astrophysics, are co-authors of the Monthly Notices of the Royal Astronomical Society: Letters article.

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Materials provided by University of Iowa. Original written by Richard Lewis. Note: Content may be edited for style and length.

However, behavioral experiments with sacred datura (Datura wrightii), which were infested by the three-lined potato beetle Lema daturaphila, resulted in an unexpected surprise: Quite obviously, female tobacco hawkmoths even preferentially laid their eggs on these Datura plants, compared to plants that were not infested by the beetles.

“To be honest, we were a little frustrated at first because we had expected the experiments to confirm our initial hypothesis, namely that egg-laying tobacco hawkmoths avoid food competitors. In our case, however, the unexpected observation suddenly made sense when we realized that beetle-infested plants smell quite differently and that parasitoid wasps, which often use plant odors to find their host insects, are less efficient at detecting tobacco hornworms on beetle-infested plants,” explains study leader Markus Knaden.

In nature, it is not always possible to avoid all dangers and at the same time select a place with abundant food. For example, studies suggest that up to 90% of Manduca sexta caterpillars are parasitized by the wasp Cotesia congregata. This parasitoid wasp lays its eggs in the caterpillars and transmits pathogens. Parasitized tobacco hornworms usually die, when the wasps’ offspring hatches.

The researchers used this knowledge to study the seemingly strange behavior of the tobacco hawkmoths in more detail. They analyzed the odor Datura plants emit when they are infested by three-lined potato beetles and compared it with control plants without infestation. And, finally, they noticed an unusual increase of the substance alpha-copaene in the plants’ odor bouquet.

How the moths detect and process this odor was the next question the team answered. Since tobacco hawkmoths have about 70 odorant receptors that would be potential candidates for detecting alpha-copaene, it would have been very time-consuming to test them all individually. Instead, a combination of complex molecular methods allowed the scientists to reduce the number of candidates from about 70 to 6, and finally identify Or35 as the odorant receptor activated by alpha-copaene and probably involved in oviposition.

The researchers also examined the odor-guided behavior of the parasitoid wasps. Choice experiments in which the wasps could choose between two odors revealed, on the one hand, that Cotesia congregata wasps preferred the odor of plants on which tobacco hawkworms were feeding to control plants. On the other hand, these behavioral assays also demonstrated that the wasps avoided the odor of plants that were infested by Lema daturaphila beetles. These results were confirmed by assays in an experimental tent containing Datura plants infested only by tobacco hawkmoths or by tobacco hawkmoths and beetles. Wasps also avoided plants with beetles in this setting.

Although the development of tobacco hornworms on plants that are additionally infested by beetles is impaired in comparison to the development of caterpillars on non-infested plants, the mother moths accept this disadvantage when laying their eggs. The advantage of protecting their offspring from parasitic wasps must therefore outweigh the disadvantage of food competition. Such cost-benefit trade-offs play a significant role in many ecological interactions. “Our results show that in nature, simple explanations are often not sufficient. Tobacco hawkmoths do not only have to take into account, whether a plant is a good food substrate for their offspring, but also whether potential competitors are already present, and whether the presence of these competitors could even help to hide from predators,” Bill Hansson summarizes the results.

Why Datura plants emit different odor depending on the insects that feed on them will be addressed in further studies. Both Manduca sexta caterpillars and the larvae of the three-lined potato beetle Lema daturaphila are chewing insects and cause similar damage to plant tissue. Presumably, microorganisms in the oral secretions of the animals play a role. Interdisciplinary approaches that also focus, for example, on the role of microorganisms in these complex interactions may help to uncover further exciting aspects of the multifaceted interactions between living organisms.

Lead author Lia Siegelman, a physical oceanographer and postdoctoral scholar at Scripps Institution of Oceanography at the University of California San Diego, decided to pursue the research after noticing that the cyclones at Jupiter’s pole seem to share similarities with ocean vortices she studied during her time as a PhD student. Using an array of these images and principles used in geophysical fluid dynamics, Siegelman and colleagues provided evidence for a longtime hypothesis that moist convection — when hotter, less dense air rises — drives these cyclones.

“When I saw the richness of the turbulence around the Jovian cyclones with all the filaments and smaller eddies, it reminded me of the turbulence you see in the ocean around eddies,” said Siegelman. “These are especially evident on high-resolution satellite images of plankton blooms for example.”

Siegelman says that understanding Jupiter’s energy system, a scale much larger than Earth’s one, could also help us understand the physical mechanisms at play on our own planet by highlighting some energy routes that could also exist on Earth.

“To be able to study a planet that is so far away and find physics that apply there is fascinating,” she said. “It begs the question, do these processes also hold true for our own blue dot?”

Juno is the first spacecraft to capture images of Jupiter’s poles; previous satellites orbited the equatorial region of the planet, providing views of the planet’s famed Red Spot. Juno is equipped with two camera systems, one for visible light images and another that captures heat signatures using the Jovian Infrared Auroral Mapper (JIRAM), an instrument on the Juno spacecraft supported by the Italian Space Agency.

Siegelman and colleagues analyzed an array of infrared images capturing Jupiter’s north polar region, and in particular the polar vortex cluster. From the images, the researchers could calculate wind speed and direction by tracking the movement of the clouds between images. Next, the team interpreted infrared images in terms of cloud thickness. Hot regions correspond to thin clouds, where it is possible to see deeper into Jupiter’s atmosphere. Cold regions represent thick cloud cover, blanketing Jupiter’s atmosphere.

These findings gave the researchers clues on the energy of the system. Since Jovian clouds are formed when hotter, less dense air rises, the researchers found that the rapidly rising air within clouds acts as an energy source that feeds larger scales up to the large circumpolar and polar cyclones.

Juno first arrived at the Jovian system in 2016, providing scientists with the first look at these large polar cyclones, which have a radius of about 1,000 kilometers or 620 miles. There are eight of these cyclones occurring at Jupiter’s north pole, and five at its south pole. These storms have been present since that first view five years ago. Researchers are unsure how they originated or for how long they have been circulating, but they now know that moist convection is what sustains them. Researchers first hypothesized this energy transfer after observing lightning in storms on Jupiter.

Juno will continue orbiting Jupiter until 2025, providing researchers and the public alike with novel images of the planet and its extensive lunar system.

Seigelman is funded through the Scripps Institution of Oceanography Postdoctoral Program, working in the lab of physical oceanographer William Young, whose work is supported by the National Science Foundation.

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Materials provided by University of California – San Diego. Original written by Lauren Fimbres Wood and Chase Martin. Note: Content may be edited for style and length.