“How indeed?” murmured Ben Hwang with a quick glance at Riordan. Once again, getting a better picture of what had been going on in this particular stellar cluster twenty millennia ago rose up as a significant, even urgent, intelligence objective. “Tell me, how do the spores work?”
“There are many different spores: a novitor or hortator would be able to provide a comprehensive explanation. My understanding is that when human secretions are detected in our environment, the small but persistent production of defense spores is triggered to enter a hyper-production stage. Some of the defense spores cause our fauna to avoid humans, some will agitate suitable species to attack, instead. But the most common variety of spores simply lodge in your mucous membranes and generate a pronounced histaminic response, as well as respiratory swelling. The sequelae include decreased cognitive clarity and mobility, thereby rendering the subject—”
“—extremely tractable,” finished Hwang.
“You perceive, then.”
“All too completely,” Hwang murmured.
“And what of you, Caine Riordan? Do you understand how very profoundly you were marked by the dying water-strider, and why?”
“I probably don’t fully understand either,” Caine confessed.
“Then I shall elucidate. The water-strider marked you more deeply and broadly than is typical outside the limits of its own species. To simplify, it marked you with powerful rapport and affinity spores when it last breathed upon you. When it rubbed you, it saturated you with compliance pheromones. That is why the water-striders are waiting to aid you.”
“And it imparted these gifts because I was kind to it when it died?”
“That is part of it, certainly, but there is something else: you have been marked before. That other mark is deep and strong, but it is also unfamiliar. I believe it is very old.”
“Yes. It happened about two years ago.”
“I do not mean that the marking occurred long ago. I mean that the marker itself is unfamiliar to today’s taxae. It seems ancient, even primal. It is — most striking.”
Ben nodded slowly. “So, you feel it yourself.”
“Yes. It is peculiar to find glimmers and scents of our unrecorded past wafting about an xenosapient such as yourself, Caine Riordan. It elicits many questions.”
I’ll bet it does. Caine was wondering whether he should let the topic slide when a flapping sound and a rising shadow distracted him. The water-strider upon which he was riding had raised the two membranous fins that had been lying folded to either side of its back-perched passengers. “Is everything all right?”
W’th’vaathi’s bifurcated prehensile tail flicked dismissively. “Our herd has detected the presence of another, downstream. Although none of us are masters of water-strider communications, I presume it is alerting the others that our approach is not a challenge or a purposive territorial encroachment.” Her tone changed. “Or they could be sending premating signals.”
“Mating signals?” Caine suddenly wanted to be off the water-strider’s back, far away from having to witness, let alone dodge, the amorous frolics of these ungainly giants.
W’th’vaathi may have been amused: one of her tails shimmied irregularly. “Allow me to be more precise. They might be exchanging expressions of interest and receptivity. For later.”
From further back on the creature’s back, Macmillan snorted. “Hey, baby, here’s my number. Call me.” If W’th’vaathi understood Macmillan’s truly alien quip, she gave no sign of it.
Caine glanced at the two ribbed and leathery fins rising up on either side; fully extended, they were more akin to long, triangular pennants. “These extensions must serve a purpose other than imparting mating signals. Stability while swimming, perhaps?”
W’th’vaathi’s head swayed gently from side-to-side: a gesture that Riordan had come to associate with tentative agreement. “Fossil records suggest that this may have been their original purpose. But that was probably before their large flippers elongated and evolved into legs. However, the force of evolution does not waste useful resources. Study the tips of the spines which raise and spread the fins.”
Caine did so and noticed that the spines protruded beyond the membrane of the fins and did not end in tapering points, but were angle-cut, akin to the nub of a quill pen. It took several moments of scrutiny before Riordan realized what he was looking at: “Are those breathing tubes?”
“Yes. When a water-strider submerges and seals the row of large respiration ducts on either side of its spine, the fins function as snorkels.”
Hwang nodded. “So, the fins’ courtship use is secondary. Tell me: do fin differences signal sex differences?”
W’th’vaathi turned from her position just behind the head of the water-strider. “As with us, and many other species that we brought to the stars, the water-striders are not gendered or sexed as is your species. Rather, among striders, there are two different reproductory variants, the impregnator and the depositor.”
“Those sound like the same things,” Macmillan murmured.
“In your heterosexual dyads, yes, but not among this species. The impregnator chooses which of the depositors it shall fertilize, as well as the kind of offspring: either a depositor or, far more rarely, another impregnator. In this way, the herd’s fertile and dominant impregnator determines the demographics of the herd, and even its genetic characteristics.”
“So why are the impregnated water-striders called depositors?” Hwang asked, hanging on to a fistful of their mount’s fur as it dipped back out into the deeper water.
“Because they do not retain the fertilized egg. It is immediately passed back to the impregnator and embeds in its womb.”
Macmillan stared. “So the impregnator is also the…the mother?”
W’th’vaathi’s left tail-half flicked once. “As I mentioned, terrestrial sexual dyadism offers few productive analogs for understanding water-strider reproduction. Caretaking and postbirth nutrition are the province of the depositor which was impregnated, not the impregnator. Also, any attempt to apply the sex-associated dominance and behavior templates common among your planet’s social mammals will be quite futile. For instance, genetic selection is not established through external forces, such as you biota’s male aggression contests, but by the impregnator’s detection of desired traits in a depositor’s pheromones.”
Riordan nodded, seeing the paradigm of Slaasriithi consensuality reprised in the water-striders. “So the evolutionary rule is not survival of the fittest, but selection of the fittest, according to the changing needs of the herd.”
W’th’vaathi’s tendrils straightened with a pop. “An apt adaptation of one of your own axioms, if I am not mistaken. And, as you may perceive, not wholly inapplicable to we Slaasriithi. Water-strider reproduction resembles ours in many particulars.”
“Och, here we go,” Keith exclaimed, “the alien ‘birds and bees’ talk. Damn, how I wish I’d stayed home in Dundee.” Caine raised an eyebrow at Macmillan who simply shrugged and smiled.
W’th’vaathi had, once again, shown no understanding of the big Scotsman’s comments. “These words baffle me, although we know of your terrestrial bee and admire many of its features.”
Ben glared at Keith who smiled sweetly in return. “Mr. Macmillan was using an idiom that refers to the — the details of mating.”
“I understand. Although I must offer an initial correction; one could not characterize any stage of Slaasriithi reproduction as mating. What humans refer to as sex — and the consequent emotional phenomena you label longing, romance, and passion — are anathema to us. Our reproductory process is partly instinctual, and partly guided by Senior Ratiocinatorae, much the way that a water-strider impregnator determines which depositor shall be fertilized.”