King of All I Survey

A few minutes later, the sap slug was high overhead. It followed the central vein of the frond in what seemed like a perfectly straight line that would eventually rake it back to the trunk of the tree.

"Is the canopy its destination or just a safe route to wherever its goal is?" Celina asked. "It may just climb down trunk and go on its way."

"Maybe," Rafael said quietly, "but I think its destination must be up there. It seems like climbing that far would be a big expenditure of energy compared to a level route across the ground. We've seen nothing that might try to prey on it. At least inside the canopy. It refused to leave the canopy at all so maybe there are things outside that would eat it. Perhaps some of those insects would burrow through its skin for the tree sap."

"Wherever its going," Celina commented, "it's taking much longer than it took to appear at the exposed sap. Either it moved much faster empty, or it was waiting much closer to the edge."

Rafael took his eyes away from the slug overhead to look at her. That hadn't occurred to him. It may have moved a little faster empty, but not much. It must have been closer to the edge waiting when it 'smelled' or detected the leaking sap.

A tight beam from the drone came back to them. "No additional sap slugs detected in expanded search area. No animal life detected on the underside of the canopy at all. Numerous small creatures moving about on the outside surfaces."

"Drone: Scan for sap slugs along the lower perimeter curtain wall, to a height of 15 feet, extend in both directions away from the entrance for two hundred yards. Include the ground up to twenty feet away from the point where the fronds touch the ground on the inside. Use a penetrating scan to a depth of fifteen feet below the ground surface." He turned his attention back to Celina who was watching the overhead slug as it continued crawling toward the tree trunk. "It couldn't have covered more distance than that between the time I made the cut and the time we saw it near the edge. The only other explanation is that it came from outside."

Without taking her eyes off the slug, Celina grinned. "You don't think like a hunter, Rafael. The slugs yesterday followed each other's trail. They must have left some residue. Just have the drone follow its trail back to its origin."

Rafael raised his eyebrows, momentarily caught off-guard by the obvious solution that he had entirely overlooked. He shook his head slightly at his own oversight. "Of course, I should have thought of that. Good call, Celina."

A wave of satisfaction washed through her, having proven her worth to him again with another idea that he had missed.

"Drone: Insert new directive ahead of the current search. Follow the residue trail of the slug from its current position back to the area where it ate the sap. From there follow the trail back to its origin. Show us the origin once it's found," He commanded.

"New directive acknowledged. Initiating."

Celina was no longer looking at the sap slug overhead. Rafael was momentarily alarmed that she had taken her eyes off it, then realized that the distance and the sap slug's transparent coloring made it too hard to follow despite its slow progress. Instead, Celina was pointing her hand held scanner in its direction and was watching it on the display screen, relying on the superior senses of the alien technology to follow it. He looked up in the direction her scanner was aimed. Even knowing the general direction, it took him more than five seconds to pick it out, his eyes finally noticed the motion of the blurred area of the frond visible through the slug's body.

"Remarkable camouflage," he commented, "Still, the drone would have spotted any no matter how good their camouflage was."

"Maybe not," Celina countered. Rafael turned sharply to look at her.

"What do you mean?" The scanner used a variety of scan wavelengths beyond the visual, it should easily find anything on the surface of the canopy or within the ground.

Still wathicng the slug's progress on her hand-held, Celina explained, "When I scanned the spa slug up-close earlier, I thought I was getting a bad reading, but I rescanned twice more with different settings to be sure. The first scan showed only the DNA of the sap inside the slug. It made upa huge percentage of the slug's mass at that point, so I figured it just hadn't focused on the thin skin or found any small organs among the mass of ingested sap. I reran the scan with a surface focus to make sure it got the slug's outer skiin." She paused. She started to turn and look at him, but remembered to keep her gaze on the scanner following the slug. "It's DNA is the same as the sap. The same as the tree itself."

Rafael stared at her for a second, "How…" Then he raised his own scanner and called up her previous scans of the slug, checking her scan parameters for each attempt. He shook his head slightly, as if denying the evidence. "It's true. Those a re good readings…" He stared at the scanner trying to process what that meant. Then he looked up at the canopy where he assumed the slug was now. He couldn't find it. It was at least a hundred feet away by now, and its lack of color to differentiate from the tree fronds made it impossible to find with his eyes alone. His gaze followed the frond to the tree trunk then down the trunk.

"The drone had that data when it scanned," he said out loud, though he was mostly clarifying his thoughts for himself. "it would be smart enough to rely on other factors during its area scans, density, shape, whatever… it would have found them, even if the DNA scan suggested it was part of the tree itself." He stood staring at the tree trunk, trying to solve the problem.

"Are the sap slugs some kind of seeds? Generated when the tree is damaged, do they absorb extra energy from the spilled sap, then use it to germinate and propel faster early growth in the new seedling? But, the new trunk we found by the entrance seems to have risen from existing roots as an offshoot ot the existing plant…"

His verbal thinking was interrupted by the drone reporting. "Sap Slug trail origin located."

Rafael looked toward the area where the drone's audible report emanated near the open entrance to the canopy. A visible beam of blue light shone out from the drone, pointing to the origin of the slug trail. It was a spot on the tree frond adjacent to the damaged frond about a foot and a half above the ground. "Keep following the one overhead," he instructed Celina.

He followed the cleared path the drone had made for them when they followed the engorged slug earlier back toward the entrance. He stopped at the indicated frond and stared at the spot where the slug's trail ended according to the drone. "Drone: Record the exact spot. Kill the blue light." He approached it and examined o his eye the frond's central vein seemed to have a slight narrowing at the spot that was roughly as long as the slug had been before it inflated with ingested sap. "Drone: Dimensional analysis. Would the volume of the unfed slug fit in that narrowingof the vein?"

"Not precisely," the drone responded, "however, the vein is expanding slowly in that area. I anticipate the narrowing will be gone within an hour at the current rate of change. It is probable that the area would have been a match for the sap slug volume at the approximate time the initial cut was made to the frond this morning."

"Remarkable. Drone: is there any evidence of an older sap slug trail leading to the depressed area of the vein from somewhere else?"

"Negative. However, the trail residue is being slowly absorbed into the frond tissue. If the older trail was much older, at least 20 hours, it could have been entirely absorbed and become undetectable."

"So not conclusive…" Rafael mumbled. "Drone: look for other such vein depressions from ground level to a height of one meter on frond veins within ten meters of the entrance opening."

"One located on the damaged frond. The trail leads to the entrance and corresponds to the captured sap slug."

Rafael nodded. "Drone: examine the fronds at the same height along the perimeter in both directions from the entrance opening for twenty meters. Use a detailed examination using whatever scan types required to determine whether sap slugs are hiding, pressed against the fronds on the other veins."

The drone moved off along the perimeter stopping for less than a second at each frond's central vein. From the far end of its search area, a few seconds later it reported, "No sap slugs found at specified locations." Then, as if realizing its precise language left some ambiguity, it continued, "Or at any location within the full scope of my examination: 0.5 meters up and down from that height."

Rafael nodded. It was starting to make sense. He looked away from the frond and back toward Celina. She had moved closer to the tree trunk following the line of the overhead frond vein, splitting her attention between picking a path and watching her scanner. She was about six or seven meters in from the canopy edge wall now. Moving carefully through the brush, Rafael walked over to join her.