Pollinator sharing and hybridization in a pair of dioecious figs sheds light on the pathways to speciation.

The dynamics and processes underlying the codiversification of plant-pollinator interactions are of great interest to researchers of biodiversity and evolution. Cospeciation is generally considered a key process driving the diversity of figs and their pollinating wasps. Groups of closely related figs pollinated by separate wasps occur frequently and represent excellent opportunities to study ongoing diversification in this textbook mutualism. We study two closely related sympatric dioecious figs (Ficus heterostyla and Ficus squamosa) in Xishuangbanna, southwest China, and aim to document what is likely to be the final stages of speciation between these species using a combination of trait data and experimental manipulation. Volatile profiles at the receptive phase, crucial for attracting pollinators, were analyzed. In total, 37 and 29 volatile compounds were identified from receptive F. heterostyla and F. squamosa figs, respectively. Despite significant interspecific dissimilarity, 25 compounds were shared. Ovipositor lengths lie well within range required for access to heterospecific ovules, facilitating hybridization. Cross introduction of wasps into figs was conducted and hybrid seeds were generated for all donor/recipient combinations. F. heterostyla wasps produce adult offspring in F. squamosa figs. While F. squamosa wasps induce gall development in F. heterostyla figs and their offspring fail to mature in synchrony with their novel host. We record limited geographic barriers, minimal volatile dissimilarity, compatible morphology, complementary reproductive phenologies, and the production of hybrid seeds and wasp offspring. These findings suggest ongoing wasp specialization and reproductive isolation, potentially applicable to other related fig species.

Correlated spectrum of distant semiconductor qubits coupled by microwave photons.

We develop a new spectroscopic method to quickly and intuitively characterize the coupling of two microwave-photon-coupled semiconductor qubits via a high-impedance resonator. Highly distinctive and unique geometric patterns are revealed as we tune the qubit tunnel couplings relative to the frequency of the mediating photons. These patterns are in excellent agreement with a simulation using the Tavis-Cummings model, and allow us to readily identify different parameter regimes for both qubits in the detuning space. This method could potentially be an important component in the overall spectroscopic toolbox for quickly characterizing certain collective properties of multiple cavity quantum electrodynamics (QED) coupled qubits.